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Importance of the archaeoseismological study for earthquake geology in South Korea
... 포항지진에 의한 액상화는 진앙으로부터 남쪽 약 9 km 거리 떨어진 포항시 남구까지도 발생하여 모래 화산(sand volcano)들이 곳곳에서 관찰되었으며 (Gihm et al., 2018;Lee et al., 2018;Gahng, 2019), 액화된 퇴적물의 분출로 인한 지반침하는 주거지, 학교를 비롯한 각종 시설물에 피해를 입혔다 (Hwang and Lee, 2018;Kim et al., 2018). Gihm et al., 2018;Jin and Kim, 2020), 실험을 통한 국내 액상화 평가 Hwang et al., 2020aHwang et al., , 2020b, 서울, 경기, 경주, 포항 등의 지역별 액상화 재해도 작성 Choi, 2019a, 2019b) et al.(1985) ...
As can be seen in many earthquakes, liquefaction causes differential settlement, which sometimes produces serious damages such as building destruction and ground subsidence. There are many possible active faults near the Busan city and the Yangsan, Dongrae, and Ilgwang faults among them pass through the city. The Busan city is also located within the influence of recent earthquakes, which occurred in the Gyeongju, Pohang, and Kumamoto (Japan). Along the wide fault valleys in the city, the Quaternary unconsolidated alluvial sediments are thickly accumulated, and the reclaimed lands with beach sediments are widely distributed in the coastal area. A large earthquake near or in the Busan city is thus expected to cause major damage due to liquefaction in urban areas. This study conducted an assessment of the liquefaction hazard according to seismic recurrence intervals across the Busan city. As a result, although there are slight differences in degree depending on seismic recurrence intervals, it is predicted that the liquefaction potential is very high in the areas of the Nakdonggang Estuary, Busan Bay, Suyeong Bay, and Songjeong Station. In addition, it is shown that the shorter the seismic recurrence interval, the greater difference the liquefaction potential depending on site periods.
... et al., 2012Choi, S.-J. et al., , 2014Lee et al., 2015;Choi, J.-H. et al., 2019;Song et al., 2020)과 고고지진학 (archeoseismology) 및 역사지진자료(e.g., Jin et al., 2011;KMA, 2014;Jin and Kim, 2020)를 종합하면, 한반도에서 지표파열을 수반하거나 그에 준하는 중 규모 이상의 지진이 간헐적으로 발생하였다. 특히 최근 발생한 두 차례의 중규모 지진인 경주지진(Mw 5.5; Kim et al., 2017)과 포항지진(Mw 5.4; Kim et al., 2018;은 한반도에서의 활성단 층과 지진발생 메카니즘에 대한 관심을 증가시켰다 (그림 1b; Kim, 2020;. ...
Deriving paleoseismological fault parameters of active faults is essential for earthquake disaster provision. The purpose of this study is to document the fault characteristics of Wonwonsa fault, which was recently reported in the 2nd fault outcrop on the eastern side of the Ulsan fault, and to provide fault parameters, such as the timing of activity. The fault slipped along the boundary between biotite granite and andesitic dike, and cuts Quaternary fluvial deposits, which deposited above basement rock. Vertical separation of about 42 cm is recognized based on the unconformity surface between the bedrock and the Quaternary fluvial deposit, but net-slip using fault geometry is calculated to be 46 cm. The burial ages of the fluvial deposits are ca. 6 ka (hanging wall part) and ca. 3 ka (footwall part) based on the optically stimulated luminescence (OSL) dating. The boulder's exposure age, which is located on the terrace surface using ¹⁰Be, was ca. 9,000 years. Although there is a difference between two dating methods, it is interpreted that this fault slipped at least once during the Holocene. Because we cannot rule out the possibility of the inheritance although it is minimal considering the steep mountain stream, the ¹⁰Be exposure had better be taken as a maximum. So, the OSL age may be near to the real age. This fault seems to have been activated after 3,600 years ago, implying that an earthquake with the surface rupture occurred during the Holocene. This result indicates the youngest active faulting age among the Quaternary faults reported along the Ulsan fault.
ecause almost all the stone cultural properties located outdoors and long time exposure to nature, the external appearance has been largely deteriorated due to natural and artificial factors such as typhoon, microorganisms, wind, moisture, extreme change in temperature, air pollutants, and salts. As we already know, damage to stone cultural properties has been accelerating particularly due to recent industrial development and environmental pollution.
For the present year 2006, Korea has designated 1,286 pieces of stone cultural properties as national treasures, which is 29.2% of the total 4,409 regarded as national treasures. These stone cultural properties are sequenced into mostly Gyeongsangbuk-do(143), Jeonllanam-do(72), Gyeongsangnam-do(58), Chungcheongnam-do(46), Gangwon-do(44), Chungcheongbuk-do(40), Seoul(35), Gyeonggi-do(33), etc. Gyeongsangbuk-do has 143 pieces of stone cultural properties as national treasures, which is 26.8% of the total 533 regarded as national treasures. For the current year 2007, Gyeongju possess 53 pieces(national treasure : 15 pieces, treasure : 37 pieces, historical site : 1 piece) of national cultural property, which is 41% of the national treasures and treasures, and 40 pieces(tangible cultural property : 21 pieces, monument : 1 piece, important folklore material : 18 pieces) of the city or provincial cultural property. Gyeongju has 130 pieces of stone cultural properties as national treasures, which is 10.1% of the total 1,286 regarded as national treasures.
The deterioration and weathering processes of stone cultural properties are classified into physical, chemical, and biological. Among these processes, physical deterioration is most destructive. But, microbial films growth on the surface of rock they change the chemical and mineralogical composition of the fresh rock and resulted in chemical and biological deterioration. Because the deterioration of stone cultural properties is interacted in a complex way, we must take into account the interrelations between phyco-chemical and biological factors. According to other researches and our on-the-spot investigations, basically most of the stone cultural properties in Gyeongju were deteriorated seriously. So, we need a study to solve the desirable procedures and the proper method for the conservation of stone cultural properties and we need it now.
Introduction:
Global Positioning System-based convergence rate between India
and southern Tibet is estimated as 20 �3 mm=yr (Larson
et al., 1999). Despite this fast convergence, the seismicity rate
of the Himalaya has been remarkably low, as only ∼50% of
this plate boundary has ruptured during the last 200 years.
This long-lived deficit in seismic productivity has led many
to believe that the region holds potential for more than one
magnitude ≥8:0 earthquake (Ambraseys and Jackson, 2003).
The Himalaya plate boundary has generated three great earthquakes
during the last century; however, since the 1950 Assam
earthquake (Mw 8.0), there has been quiescence, with the gap
in time and space particularly noted on its central segment.
Khattri (1987) proposed that the region comprising the
Garhwal and Kumaun provinces and the western parts of
Nepal falls in a seismic gap. Referred to as the “Central Gap,”
this region covers ∼600 km length of the Himalayan arc, and
it arguably represents an unruptured segment between the
sources of the 1905 Kangra M 7.8 and 1934 Nepal–Bihar
M8.0 earthquakes (Fig. 1). However, the extent to which older
earthquakes might have filled the gap is contested on various
counts. The uncertainties in locations and magnitudes of pretwentieth
century earthquakes; in particular the 1803 and
1505 events, are also being debated (Ambraseys and Douglas,
2004; Rajendran and Rajendran, 2005, 2011). Considering the
large and densely populated regions that are likely to be affected,
reconstructing the seismic history of the Himalaya is
a key issue in the seismic-hazard assessment.
The history and cultural heritage of the regions within the
central gap is much longer than the currently estimated interseismic
interval of ∼500 years for great earthquakes; and, therefore,
it provides opportunity to interrogate these issues. For
example, the state of the Hindu temples built as early as
fifth–sixth century A.D. is suggestive of the events that might
have affected them. Thus, we regard the heritage structures
of the Kumaun–Garhwal Himalaya as archeological seismic
sensors that can be used to assess the history of damaging
earthquakes. We are not aware of any studies on the seismic
performance of the temples in the Garhwal Himalaya, but
models of the performance of similar multistoried structures
in Nepal show a fundamental time period less than 0.6 s (Jaishi
et al., 2003). Because this is within the range of natural period
of a wide variety of soils, there is a high probability for such
structures to approach a state of partial resonance during large
earthquakes. The spatial distribution of damage, response of
specific structures, and models based on their structural elements
could lead to the location and magnitude of pre-twentieth century
earthquakes.
The architectural style showed only minor variations between
different clans and their rulers, and the constructions
generally consist of a common plan, which used large and heavy
rock units arranged on top of each other, without mortar
(Fig. 2). As a society whose social milieu revolved around
the temples for ages (>1000 years), the temple archives carried
through generations serve as an important and often the only
source of information on its history including the impact of
major natural calamities. Interpretation of such records is,
however, challenging due to biases in reporting, inconsistencies
in the calendars, errors in translating scripts, shifting of the
province capitals, and renaming of towns and cities. Further,
the historical structures have often been affected by territorial
wars, vandalism, and other nondocumented reasons. Despite
these interpretational limitations, we believe that the historical
archives provide useful clues for isolating time windows for
potential earthquake-related damage (e.g., Rajendran and
Rajendran, 2002). In this paper we use the historical background
and the present state of some of the heritage structures
to obtain spatial and temporal constraints on three significant
earthquakes: A.D. 1255, 1505, and 1803. The 1803 earthquake
is used as a calibration event because its effects on heritage
structures are well evidenced even in the Gangetic plains.
Observations from the 1991 Uttarkashi (Mw 6.8) and the
1999 Chamoli (Mw 6.6) earthquakes provide additional comparative
constraints (Figs. 1 and 3 for locations).
The Eupcheon Fault, one of more than 20 identified Quaternary faults recently reported in the area around the Yangsan and Ulsan faults, SE Korean Peninsula, was discovered during the construction of a primary school in an area close to a nuclear power plant. We analysed a trench excavated across the Eupcheon Fault with the aim of understanding its movement history and kinematics. The Eupcheon Fault is a reverse fault (strike/dip: N20 degrees E/40 degrees SE) that records 6-7 m of displacement (3-4 m vertical separation). The fault consists of a series of branch faults, associated fault-related folds, and rotated pebbles. A previous study reported that the fault originally recorded normal slip but was reactivated during the Quaternary as a reverse fault. We identified four or five Quaternary faulting events upon the fault based on an interpretation of the trench logs including an analysis of colluvial wedges, and measurements of displacement-distance (d-x) relationships along the fault. We used a quantitative analysis of d-x relationships, commonly used for consolidated sedimentary rocks, to interpret the deformation history of the fault. From this we estimated the amount of slip in the range of 0.7-1.8 m for each of the five identified faulting events and the earthquake magnitude in the range of M(w) 5.4-7.4. We propose two ideal d-x profiles for syndepositional and post-depositional faulting, and a tectonic evolution model for the area around this fault. This approach may be applicable to analyses of earthquake hazards and studies of fault evolution elsewhere.
The KIER's Korean historical earthquake catalog was revised for MMIVI events recorded from the years 27 A.D. to 1904. the magnitude of each event was directly determined from the criteria suggested by Seo. The criteria incorporated the damage phenomena of the Japanese historical earthquake catalog, recent seismological studies, and the results of tests performed on ancient structures in Korea. Thus, the uncertainty of the magnitudes of the Korean historical earthquakes can be reduced. Also, the Gutenberg-Richter parameter values were estimated based on the revised catalog of this study. It was determined that the magnitudes of a maximum inland and minimum offshore event were approximately 6.3 and 6.5, respectively. The Gutenberg-Richter parameter pairs of the historical earthquake catalog were estimated to be a=5.320.21, b=0.950.19, which were somewhat lower than those obtained from recent complete instrumental earthquakes. No apparent change in the Gutenberg-Richter parameter is observed for the centuries of the seismically active period.
Using the main constructive typologies used earlier than 20th Century, especially those related to the historical heritage, this paper correlates the different EAEs with the macroseismic scales EMS-98 and ESI-07. We propose minimum and maximum intensity levels for different building types, such as those related to the use of adobe, stone, brick and masonry. This work aims to establish preliminary seismic intensity intervals from the nature and styles of seismic deformations in historical buildings that can be applied to the archaeseismological analysis of heritage buildings and archaeological sites.
During the last decades the ruins of Roman-Byzantine cities in the Negev desert of Israel have been the subject of intensive archeoseismic studies. A set of earthquake damage patterns was determined and several large scale earthquakes were identified as having occurred during the 2nd to 7th centuries AD. The ruins of buildings of the small village of Halssa provided a recent study of earthquake damage patterns that evolved quite recently—during the last 110 years.
The long-term recurrence patterns of past earthquakes are of considerable consequence for hazard assessments, and have implications for earthquake physics. We introduce a rigorously dated record of earthquakes from an extensive number of well-preserved preseismic and postseismic precipitates from caves located off the Dead Sea transform. We dated events directly at the paleoseismic contact by means of a novel correlation method with the oxygen isotope record of the speleothems recovered in one of the caves. Within the 185 k.y. covered, we dated 38 seismite samples. These stem from 13 18 earthquakes with a mean recurrence interval of ˜10 14 k.y. We show that the deformational events dated in the study caves complement independent near-fault paleoseismic records by temporal correlation with the earthquakes recorded therein. This opens up a significant new avenue of earthquake research that will provide precise dating and observational constraints on large infrequent earthquakes.
Recently, a fallen Buddha statue of the late-8th century was discovered in Mt. Nam, Gyeongju, SE Korea. The Gyeongju area is located in intersection of two major young structural features in Korea: the Yangsan and Ulsan faults. According to historical records, such as the ancient texts of Samguksagi, Chaljubongi, and Mukseojipyeon, the studied area was significantly affected by several large earthquakes of MM Intensity = VII and estimated magnitude up to ML = 6.7, such as the destructive events occurred in 768 AD, 779 AD and 1036 AD. Especially, the last two earthquakes are historically well documented as triggering severe damages in other historical buildings (Hwangryongsa pagoda and Bulguksa temple) around the area. This paper examines the potential connection between the fallen Buddha statue and any of the large historical earthquakes documented in the area. Restoration study of the original position of the fallen Buddha statue, based on fracture analysis, indicates that the fallen Buddha statue rotated 20° clockwise and slid a few meters from its original position during a large rockfall event. Preliminary OSL dating was carried out from weathered soil below a large granite block adjacent to the fallen statue. The age of 0.76 ± 0.12 ka indicates a bracketed time-period between the years 1130 and 1370 AD for the statue fall. However, no earthquake is reported for this time-period in the area. Although the available data does not exactly indicate any specific earthquake, based on the historic records, artistic styles, differential weathering of the statue, OSL dating and nearby historically documented archaeoseismic damage, the 1036 AD earthquake (ML = 6.4) is proposed as the more likely event responsible for the studied damage. Furthermore, other earthquake damage to historic heritage sites was also reported in historical records around the study area. Therefore, a future seismic hazard study should be carried out to preserve the important national heritage sites in this area. The combination of paleoseismological and archaeoseismological studies is essential to estimate potential earthquake hazard in this area.
Introduction.
Population growth and increasing urbanization in earthquake-prone areas suggest that earthquake impacts on human populations will increase in the coming decades. Recent large earthquakes affecting large populations in Japan, Haiti, Chile and New Zealand are evidence of this trend and also illustrate significant variations in outcomes such damage and mortality levels. The objectives of this review were to describe the impact of earthquakes on human populations in terms of mortality, injury and displacement and, to the extent possible, identify risk factors associated with these outcomes. This is one of five reviews on the human impact of natural disasters.
Methods.
Data on the impact of earthquakes were compiled using two methods, a historical review from 1980 to mid 2009 of earthquake events from multiple databases and a systematic literature review of publications, ending in October 2012. Analysis included descriptive statistics and bivariate tests for associations between earthquake mortality and characteristics using STATA 11.
Findings.
From 1980 through 2009, there were a total of 372,634 deaths (range 314,634-412,599), 995,219 injuries (range: 845,345-1,145,093), and more than 61 million people affected by earthquakes, and mortality was greatest in Asia. Inconsistent reporting across data sources suggests that the numbers injured and affected are likely underestimates. Findings from a systematic review of the literature indicate that the primary cause of earthquake-related death was trauma due to building collapse and, the very young and the elderly were at increased mortality risk, while gender was not consistently associated with mortality risk.
Conclusions.
Strategies to mitigate the impact of future earthquakes should include improvements to the built environment and a focus on populations most vulnerable to mortality and injury.
The arch is a very common masonry structure that has been studied extensively in the past. Despite this, no analytical methods exist that can adequately evaluate the collapse mechanisms and their related loads. This paper presents a collapse approach that takes into account the small tensile and shear strengths of masonry material according to a no-tension constitutive model. Some appropriate analytical functions are proposed that can reproduce the collapse mechanisms and the values of the associated horizontal limit thrusts at the arch's skewback. This approach also provides the minimum value for the thickness-span ratio, the safety margin, and the maximum value of uniformly distributed vertical loads (load parameter). The collapse mechanisms' shapes and the horizontal limit thrusts are then analyzed as a function of the loads and the arch's geometry. In addition, the findings are compared to the results of a finite-element analysis.
EXAMINATION of archaeological sites and records in the Levant reveals features of destruction attributable to ancient earthquakes, which may help in verification of old earthquake catalogues and in assessment of seismic hazards.
Thessaly, Central Greece, like most of the Aegean realm is characterised by a diffuse seismic activity. Both instrumental and historic data are revised and, with few exceptions, this information substantiates that the local seismicity is characterised by a shallow seismogenic depth that can generate important destructions though distributed to limited areas. However, historical sources like diaries and church books or, for more recent events, newspapers are almost completely lacking before the 17th century. On the other hand, recent palaeoseismological surveys carried out along some of the active faults of Eastern Thessaly clearly document the occurrence of past earthquakes during latest Pleistocene and Holocene times. The present research is an attempt of partially filling the gap of our knowledge on the seismicity of the area. At this regard, we followed the methodological approaches of the Historical Seismology and the Archaeoseismology. In particular, we focused our investigations on the interpretation of both direct and indirect evidences issued from Greek inscriptions, monuments and settlements of Ancient and Byzantine times. Special emphasis is given to the recently discovered Great Theatre of Larissa that shows important evidences of seismically induced damages. We analyse all this information with the intention of reconstructing the late Holocene seismic evolution of the northeastern sector of Thessaly, while the final aim of this article is the seismic hazard assessment of this region, whose major urban centre is Larissa that represents the third town of Greece.
One of the key tasks in archaeoseismolo`gy is to test whether the recorded building damage in ancient cities can be related to ancient earthquakes. Archaeologists often claim abandonment, ruin or war instead of natural causes to explain the recorded damage in archaeological findings. This work proposes a comprehensive classification of Earthquake Archaeological Effects (EAE) based on the seismic deformation of buildings and monuments within urban areas of ancient cities. Accordingly, the proposed EAE classification differentiates the seismic deformation on the structure of buildings in two groups: from transient shaking and from permanent ground deformation. The first type of EAE corresponds to fractured walls and fallen key stones in arches, for example. The second type of EAE are tilted walls and shock breakouts of flagstones due to basement failure. To illustrate the proposed EAE classification, examples of earthquake damage on ancient buildings are described: Baelo Claudia and Tolmo de Minateda cities (Roman and Visigothic Periods, 1st–6th century AD, respectively, South of Spain) and Teotihuacán and Tarascan sites (Early Classic ca. IVth century AD, and Upper Post-Classic Period XIIIth century AD, Central Mexico).
The Dead Sea fault zone is a major left-lateral strike-slip fault. South of the Dead Sea basin, the Wadi Araba fault extends over 160 km to the Gulf of Aqaba. The Dead Sea fault zone is known to have produced several relatively large historical earthquakes. However, the historical events are unequally distributed along the fault and only four events have been reported in the Araba valley over the last few thousands of years. Magnitudes estimated from the historical record are probably slightly smaller than that of the M_w ∼ 7.3 earthquake that struck the Gulf of Aqaba in 1995. The fault cuts straight across Pleistocene to Holocene alluvium and shows morphologic evidence for essentially pure strike-slip motion. Regional seismic monitoring reveals little microseismicity along the fault except around the Dead Sea and Gulf of Aqaba, where the fault splays into complex pull-apart basin fault systems. We have investigated the fault zone at several sites selected from SPOT images and the study of aerial photography. At the site of the now destroyed Tilah Castle, a well-preserved wall, dated to be about 1200 yr BP (^(14)C age on charcoal), is cut by the fault and offset by 2.2 m. Comparison with offset gullies at a nearby site 3 km to the north and at three other sites, respectively 25, 50 and 65 km to the south, reveals that this specific fault displacement is probably related to the last seismic event that ruptured that fault segment, possibly in AD 1458.
Moreover, the offset gullies suggest a characteristic slip behaviour with recurring slip of about 1.5 m on average. Given the 4 ± 2 mm yr^(−1) slip rate derived for this fault segment, we infer that the fault should produce M_w ∼ 7 earthquakes along some segment in the Araba valley about every 200 years. The historical period, with only four well-documented large earthquakes in AD 1068, AD 1212, AD 1293 and AD 1458, thus appears to have been relatively quiescent, with a 20 per cent deficit of M_w ∼ 7 earthquakes. However, our data do not exclude the possibility of larger M_w ∼ 7.6 earthquakes or time clustering of earthquakes over longer timespans. An alternative seismic behaviour involves M_w ∼ 7.6 earthquakes about every 6000 years and M_w ∼ 7 earthquakes about every 250 years. The historical catalogue would then appear to be complete for M_w ∼ 7 earthquakes.
The archaeological site of Qasr Tilah, in the Wadi Araba, Jordan is located on the northern Wadi Araba fault segment of the Dead Sea Transform. The site contains a Roman-period fort, a late Byzantine–Early Umayyad birkeh (water reservoir) and aqueduct, and agricultural fields. The birkeh and aqueduct are left-laterally offset by coseismic slip across the northern Wadi Araba fault. Using paleoseismic and archaeological evidence collected from a trench excavated across the fault zone, we identified evidence for four ground-rupturing earthquakes. Radiocarbon dating from key stratigraphic horizons and relative dating using potsherds constrains the dates of the four earthquakes from the sixth to the nineteenth centuries. Individual earthquakes were dated to the seventh, ninth and eleventh centuries. The fault strand that slipped during the most recent event (MRE) extends to just below the modern ground surface and juxtaposes alluvial-fan sediments that lack in datable material with the modern ground surface, thus preventing us from dating the MRE except to constrain the event to post-eleventh century. These data suggest that the historical earthquakes of 634 or 659/660, 873, 1068, and 1546 probably ruptured this fault segment.
Excavations in the former Roman provincial capital of Pannonia Superior, Carnuntum, 40km east of Vienna revealed damaged masonry structures from many parts of the ancient settlements. A compilation of structurally damaged buildings has formerly been given by Kandler (Acta Archaeol Acad Sci Hung, 41:313–336, 1989), who related damage to an earthquake in the middle of the fourth century a.d. This paper reviews and supplements these data, and discusses the significance of the style of damage. It is concluded that seismic damage is the only likely interpretation for the damaging mechanism. Although archaeological age dating for the individual collapsed buildings only constrains the timing of their destruction to a few decades around 350a.d., we assume a single damaging event. In spite of the restrictions on damage assessment by the nature of the archaeological data, it is possible to give a reasonable appraisal of macroseismic intensity. The tentative seismological interpretation of damage leads to an intensity estimate of about nine of the European macroseismic scale (EMS-1998). Comparison with macroseismic data of modern earthquakes in the region, which show a rapid decrease of intensity with distance form the epicentre, indicate a near-by seismic source unless exceptionally high epicentral intensities are assumed for the fourth century event. The most likely source is an active sinistral strike-slip fault (Lassee Fault) passing about 8km NW of the archaeological site. The fault belongs to Vienna Basin fault system with about 2mm sinistral movement per year. The system is characterized by fault segmentation and distinct seismicity along the different segments. Moderate seismicity during the last centuries at the southern segments (e.g., Schwadorf 1927, I
0=8) strongly contrasts from the Lassee fault segment with Carnuntum as the only known severe earthquake. The earthquake of Carnuntum provides evidence for the overall seismic style of deformation along this segment, which previously has not been regarded seismically active. Also, the fourth century earthquake is the strongest event known from the Vienna Basin fault so far.
The investigation of past earthquakes can be approached in many different ways with a large variety of methods and techniques. This is mainly due to the complexity of this natural phenomenon in both its genetic aspects and consequential ones. In the present note, we briefly analyse the peculiarities of Instrumental Seismology, Historical Seismology, Archaeoseismology and Earthquake Geology, but especially we emphasise the major differences among these four distinct approaches. In order to better define and clearly separate these disciplines, in terms of appropriate tools to be applied and possible outcomes to be expected, an alternative point of view is proposed based on the source of information and not on a chronological distribution as commonly accepted in the literature. Although multidisciplinarity is a common approach for investigating past earthquakes, each one of the discussed disciplines has its own peculiarities, advantages and limitations, and researchers should be aware of this.
The Wadi Araba Valley is a morphotectonic depression along part of theDead Sea Transform (DST) plate boundary that separates the Arabian plateon the east from the Sinai subplate on the west. The Wadi Araba fault(WAF) is the main strike-slip faults one of between the Gulf of Aqaba and the E-Wtrending Khunayzira (Amatzayahu) fault that bounds the southern end ofthe Dead Sea. Just south of the Dead Sea, the WAF cuts across severalgenerations of alluvial fans that formed on tributaries to the Wadi Dahalafter the regression of Late Pleistocene Lake Lisan ca. 15 ka. Geomorphicand stratigraphic evidence of active faulting, including left-laterally offsetstream channels and alluvial-fan surfaces, yielded fault slip-rate data for thenorthern segment of WAF. Typical cumulative displacements of 54 m,39 m, and 22.5 m of stream channels and alluvial-fan surfaces acrossthe fault were measured from detailed geologic and topographic mapping.The 54 m offset of the oldest alluvial-fan surface (Q
f1
) occurredafter the final lowering of Lake Lisan (16–15 ka) and before 11 ka yieldinga slip-rate range of 3.4 mm/yr to 4.9 mm/yr. Based on radiocarbonages of charcoal and landsnail shell samples from the buried Q
f2
alluvial-fan deposits exposed in trenches excavated across the fault, the39 m and 22.5 m offsets occurred after 9 ka and 5.8 ka, respectively. These data yield a slip-rate range between 3.9 mm/yr and 6.0 mm/yr.The small variability in these slip-rate estimates for different time periodssuggests that the northern Wadi Araba fault has maintained a relativelyconstant slip rate in the past 15 ka. We calculate an average slip rate of 4.7 1.3 mm/yr since 15 ka based on the three separate displacementsand age estimates. Five separate offsets of 3 m were measured from gullybends and the offset of small fault-scarp alluvial fans. These displacementdata suggest a coseismic slip of 3 m in the last earthquake, or acumulative slip of 3 m in the past few earthquakes. A maximum slip of3 m correspond to a Mw 7 earthquake that ruptures about 49 km offault length. Using an average slip rate of 4.7 1.3 mm/yr togetherwith a 3-m slip-per-event suggests a maximum earthquake recurrence intervalof this fault segment of 500 to 885 years.
To provide quantitative information on the ground acceleration necessary to break speleothems, laboratory measurements on samples of stalagmite have been performed to study their failure in bending. Due to their high natural frequencies, speleothems can be considered as rigid bodies to seismic strong ground motion. Using this simple hypothesis and the determined mechanical properties (a minimum value of 0.4 MPa for the tensile failure stress has been considered), modelling indicates that horizontal acceleration ranging from 0.3 m/s2 to 100 m/s2 (0.03 to 10g) are necessary to break 35 broken speleothems of the Hotton cave for which the geometrical parameters have been determined. Thus, at the present time, a strong discrepancy exists between the peak accelerations observed during earthquakes and most of the calculated values necessary to break speleothems. One of the future research efforts will be to understand the reasons of the defined behaviour. It appears fundamental to perform measurements on in situ speleothems.
Studies to provide information concerning seismic parameters and seismic sources of historical and archaeological seismic events are used to better evaluate the seismic hazard of a region. This is of especial interest when no surface rupture is recorded or the seismogenic fault cannot be identified. The orientation pattern of the earthquake damage (ED) (e.g., fallen columns, dropped key stones) that affected architectonic elements of cities after earthquakes has been traditionally used in historical and archaeoseismological studies to infer seismic parameters. However, in the literature depending on the authors, the parameters that can be obtained are contradictory (it has been proposed: the epicenter location, the orientation of the P-waves, the orientation of the compressional strain and the fault kinematics) and authors even question these relations with the earthquake damage. The earthquakes of Lorca in 2011, Christchurch in 2011 and Emilia Romagna in 2012 present an opportunity to measure systematically a large number and wide variety of earthquake damage in historical buildings (the same structures that are used in historical and archaeological studies). The damage pattern orientation has been compared with modern instrumental data, which is not possible in historical and archaeoseismological studies. From measurements and quantification of the orientation patterns in the studied earthquakes, it is observed that there is a systematic pattern of the earthquake damage orientation (EDO) in the proximity of the seismic source (fault trace) (<10 km). The EDO in these earthquakes is normal to the fault trend (±15°). This orientation can be generated by a pulse of motion that in the near fault region has a distinguishable acceleration normal to the fault due to the polarization of the S-waves. Therefore, the earthquake damage orientation could be used to estimate the seismogenic fault trend of historical earthquakes studies where no instrumental data are available.
Deformed arches are often key elements of archaeoseismic studies; arches have been in use for more than three millennia and damage, particularly moved keystones, are clear indications of a seismogenic cause. We introduce a damage evaluation scheme that allows a straightforward determination of the degree of damage to an arch based on laser scan models and digital images. The scheme is applied to 90 arches of the Nimrod Castle, which is neighboring the Dead Sea fault and which was heavily damaged during the 1759 Lebanon earthquake. The analysis shows that the a priori assumption of a correlation between arch orientation and damage degree does not hold for the entire building. An exception is a large tower including a secret passage in which voussoirs have dropped along a more than 20 m long section.
Over 250 detailed observations of severe earthquake damage patterns were decoded at the complex of Nabatean-Roman-Byzantine buildings at the ancient desert settlement Mamshit. T h e seismic deformation patterns are of various types, including systematic tilting of walls, systematic rotation o f stones, slipped key stones of arches, walls pushed by displaced perpendicular walls, cracking of doorsteps and lintels, joints crossing two or more stones, bulging of central segments of walls. The joint occurrence of systematic tilting and systematic rotations serves as an internal check that the former were caused by earthquakes. Each of t h e specific deformation patterns defines boundary conditions that together disclose the anatomy of two devastating earthquakes: 1. at the end of the 3rd or beginning of the 4th cent, (revealed by the lower parts of buildings, built at the Roman period), with a paleoepicenter north of Mamshit, an seismic intensity probably of IX in EMS-98 Scale, the activated fault being situated at t h e Judean Desert; 2. at the 7th cent, (revealed by the upper parts of buildings restored and built at the Byzantine period), with an epicenter at SW, an intensity of IX EMS-98 scale, the probable reactivated fault being one of the several E -W fault lines that cross the Negev. Regarding.the anatomy of the earthquakes, the results indicate that in each earthquake event there was a dominant damage-causing factor - as is reflected in the directional damage patterns.
Plate-tectonic theory explains earthquakes at plate boundaries but not those in continental interiors, where large earthquakes often occur in unexpected places. We illustrate this difference using a 2000-year record from North China, which shows migration of large earthquakes between fault systems spread over a large region such that no large earthquakes rupture the same fault segment twice. However, the spatial migration of these earthquakes is not entirely random, because the seismic energy releases between fault systems are complementary, indicating that these systems are mechanically coupled. We propose a simple conceptual model for intracontinental earthquakes, in which slow tectonic loading in midcontinents is accommodated collectively by a complex system of interacting faults, each of which can be active for a short period after long dormancy. The resulting large earthquakes are episodic and spatially migrating, in contrast to the more regular spatiotemporal patterns of interplate earthquakes.
The former Roman city of Hierapolis (modern Pamukkale), within the Büyük Menderes valley, contains an abundance of faulted architectural relics related to damaging earthquakes that have occurred since at least 60 A.D. Faulted relics include: (1) a Roman fresh-water channel; (2) a mid-Roman relief carved into a fault plane; (3) Roman and Byzantine walls offset across the Hierapolis normal fault zone; (4) the walls of a late Byzantine fort offset more than once across a fissure/fault; and (5) numerous displaced wall-like Roman and post-Roman petrified water channels. In addition to these faulted relics, numerous monuments display tilted and toppled walls; maximum damage generally being adjacent to the Hierapolis fault zone which passes through the centre of the city. Many relics are also partly covered by faulting-related travertine deposits.Analysis of the faulted relics indicates: (1) Hierapolis and its immediate surroundings are cut by two active normal fault zones; (2) the NNW-trending Hierapolis fault zone, formerly thought to be a sinistral strike-slip fault, is a small normal fault zone; (3) there has been about 1.5 m of normal slip on the Pamukkale range-front fault since mid-Roman times; (4) an opening direction across the weakly expressed Hierapolis fault zone can be inferred by matching formerly contiguous piercing points on the relic that are now on either side of the fault trace; (5) where a fault passes through a narrow rigid architectural relic, its trace is generally refracted so that it is oriented at roughly right angles to the long axis of the relic; and (6) some major dilated cracks cutting relics reflect the locations of underlying faults.
Studies of ancient seismicity in the Levant are based on the interpretation of biblical, ecclesiastic and historic chronicles, all of which are plagued by exaggeration and misinterpretation. To verify the occurrence of such ancient earth-tremors, archaeological archives in Israel were searched for reports and evidence of ancient catastrophic damage, attributable to earthquakes. Literature and response to questionnaires revealed about 20 sites at which features of ancient destruction were assigned a seismic origin. The actual field evidence included horizons of total destruction, and mainly features of fracturing (joints, fissures, cracks and faults), tilting and subsidence, directed collapse and parallel alignments of fallen columns and masonry. About 75% of these sites lie within or near to the Dead Sea-Jordan Rift, confirming the seismogenic nature of this zone. In spite of their significance and usefulness, the archaeoseismic data cannot be employed as an entirely independent technique for the verification of ancient chronicles and the study of past seismicity. In addition to problems of operator's bias, and bias due to historic information, the critical examination of field evidence cited in support of ancient seismicity has shown that the individual features are difficult to distinguish from features of damage due to poor construction and adverse geotechnical effects. It is essential therefore, in the description of ancient damage and of consideration of its origin, to maintain a proper balance between geological, geomorphological and geotechnical factors on one hand, and historic, anthropogeographic and archaeological factors on the other.
Is it really plausible that earthquakes break speleothems? May unbroken speleothems prove that no strong earthquake has ever occurred during a certain period of time? The mechanical behaviour of speleothems has been investigated through static bending tests performed on stalactites and soda straws. These tests give an indication not only of the mean tensile resistance, but also—more importantly—of its variation. In fact, it is this variation that makes it difficult to estimate the acceleration necessary to break an individual speleothem. That is why a statistical approach is mandatory. The potentially most vulnerable unbroken as well as broken stalactites were measured in a pilot cave (Milandre, Switzerland). Four classes of stalactites were denned, according to their shapes. For each of these classes, a vulnerability curve (probability of breaking as a function of peak ground acceleration) was obtained by means of a Monte Carlo simulation. Dynamic amplification as well as heterogeneity of bending resistance within each speleothem were taken into account. Finally, an original statistical approach, valid for incomplete and imprecise data, was developed. This approach allowed to estimate the probability that at least one moderate earthquake has occurred in the past.
Reflecting on the burgeoning scientific discipline of archaeoseismology, a clear trend can be discerned. What started as an “extravaganza” in a good story (archaeological perspective) became a multidisciplinary effort to get a maximum amount of information on the parameters of ancient earthquakes out of archaeological evidence (seismological and archaeoseismological perspective). A clear shift can be observed from a more qualitative approach focussing on the extension of earthquake catalogues to a more quantitative approach concerning site effects. Looking into the future, the vocation of archaeoseismology may lie elsewhere. Archaeoseismology could become a holistic interdisciplinary discipline concerned with establishing the essential earthquake culture in a region (sociological perspective).
Historical records of earthquakes can contribute significantly to understanding active faulting and seismic hazards. However, pre twentieth century historians were unaware of the association of earthquakes and fault ruptures. Consequently, historical texts usually report the time and damage caused by earthquakes, but not the associated faults. Conversely, observed fault ruptures are often difficult to date. In order to overcome these difficulties, we have analyzed archaeological and sedimentological observations in recent excavations in the ancient city of Tiberias and have combined them with interpretation of historical accounts. Tiberias was founded in A.D. 19 by King Herod on the western shore of the Sea of Galilee (Kinneret). Herod's stadium, exposed in these excavations for the first time, was damaged by boulder-bearing flash floods and by an earthquake. Later buildings, dated as late as the early eighth century, are all covered by alluvium and lake deposits. They are also damaged and offset by normal faults, whereas buildings from the late eighth century are intact. We therefore attribute the damage to the earthquake of 18 January 749. The paleoseismic observations are in good agreement with the distribution of damage on the basis of historical records. Both data sets indicate a 100-km-long rupture segment between the Kinneret and the Dead Sea pull-apart basins, demonstrating that it is capable of generating M > 7 earthquakes.
Several sets of marine terraces are exposed along the southeastern coast of the Korean peninsula. The formation ages of these terraces have attracted considerable attention because they provide essential information on local crustal stability. Over the last few years considerable effort has been put into the determination of these ages using optically stimulated luminescence (OSL) dating of the marine sediments from which the terraces were built. For several sites, the results of dose recovery tests and other OSL characteristics, including the dependence of equivalent dose on heat treatment prior to stimulation, have been described in detail elsewhere (Quat. Sci. Rev. 22 (2003) 407). However, it has been found that the samples from one site exhibit various undesirable OSL characteristics, which result in stratigraphically inconsistent OSL ages. In this paper, we investigate these characteristics, and use luminescence component separation to resolve this inconsistency. The resolved OSL ages obtained as such are then used for the discussion on the local crustal stability of the southeastern coast of Korea during the Late Pleistocene.
The behavior of filled masonry arch bridges under truck loading is examined by service load testing and by developing a finite-element model of a unit width of the structure. The held tests included five structures varying in span from 3 to 12 m. The structures tested included a group of three structures of similar geometry, material, age, and geographic location. The testing program demonstrated the significance of the linearity of the response to different loading levels and the importance of permanent deformations in evaluating a structure. The field tests also gave evidence of the range of responses of similar structures, and showed some evidence of the development of an incipient mechanism. The analytical model included approximation of the load distribution through the fill and the restraint to movements of the arch ring developed by the fill and spandrel walls. Reasonable approximations of the experimentally observed response of the structures were obtained using the analytical model. Guidance in selecting material properties and stiffnesses for the abutments and fill-in modeling masonry arch structures is given.
The masonry arch as a system of rigid voussoirs subject to unilateral constraints has been investigated applying the principle of virtual work in order to define a general criterion providing the necessary and sufficient conditions for the equilibrium of the system. Since the assumptions of the formulation coincide with those of the preelastic theories, the main historical approaches have been revisited, showing that their criteria are encompassed in the present formulation. A parametric analysis has been carried out with reference to geometry and friction for a semicircular arch of constant thickness and subject to its own weight. The ranges of values for the thrust at the crown required for the equilibrium to exist have been thus determined and a geometric safety factor has been defined. A comparison of these results for the arch of minimum thickness with those obtained from the historical theories and more recent formulations has also been made.
The Gesher site is located in the Kinnarot Valley in the Dead Sea Rift, Israel. Excavations, at the site revealed in situ Pre-Pottery Neolithic A (∼10,000 years BP) and Middle Bronze Age (∼4,000 years BP) remains. Exposures produced during construction works and archaeocological excavations show a complex pattern of Late Pleistocene-Holocene faulting and tilting. The exposures at the Gesher site exhibit displacements on two discrete fault systems. The first is a normal displacement of about 1 m of Lisan Fm. deposits and the overlying Neolith layer on apparently E-W-trending faults. Most probably the faulting manifests a rejuvenation of displacement on the lateral extension of the E-W-trending normal fault the valley shoulders. The proposed timing of faulting is the age of the overlying sediments of the Fatza'el Mbr., 8,000-10,000 years BP. A second fault system shows at least two episodes of displacement on nearly N-S-trending faults. Faulting and tilting of Lisan Fm. deposits that produced disconformity in the upper layers suggest that the first stage of tectonic deformation on the western faults occurred during the existence of Lake Lisan. A sample of the Lisan Fm. located near the disconformity yielded 14C age of about 25,000 years BP. Post Fatza'el Mbr. displacements on the N-S faults manifest both normal faulting and tilting, and most probably a lateral slip, related to the motions along adjacent plate border faults or on the border faults of the Shomeron Triangle structure. The faults could produce earthquakes: the westward normal faulting and tilting at about 25,000 years BP and E-W normal faulting at about 10,000 years BP represent relatively strong seismic events that occurred before 8,000 years BP. Good preservation of fine remnants of the cultural laye r is attributed to rapid covering of the site area by a fresh-water body in which the fine sediments of the Fatza'el Mbr. were deposited. This provides an age of ∼10,000 years BP for the start of a wet climatic period during the Pleistocene-Holocene transition. The elevation of the Gesher site Neoli thic remains at -240 m rules out the possible existence of the Bet She'an Lake at that time.
Abstract Two groups of Quaternary faults occur in the southeastern Korean Peninsula. The first group is north-northeast-striking, high-angle dextral strike–slip faults. The second group is north-northeast-striking, low-angle reverse faults that represent the reactivation of the pre-existing normal faults. Optically stimulated luminescence dating of Quaternary sediments cut by one of the reverse faults constrains the faulting age to post-32 Ka. These faults seem to be capable of further slip under the current tectonic stress regime, as determined by recent earthquake events in northeast Asia. Therefore, the traditional concept that the southeastern Korean Peninsula is seismically stable should be reappraised.
This paper summarizes evidence for surface faulting in historical and recent earthquakes in the Eastern Mediterranean region and in the Middle East. Such information is particularly important for studies of active tectonics and for palaeoseismology. We have found 78 cases of faulting pre-1900 and 72 post-1900, some of which show that faults that have apparently been inactive this century had already ruptured before 1900. For some cases faulting could not have been predicted from 20th century activity, and in others it could have been expected, but has not been observed during the instrumental period. The data are sufficient to allow the derivation of relationships between magnitude and rupture length.
The Korean peninsula lies in the Eurasian plate, neighboring seismically active China and the Japanese Islands. Instrumental observation of earthquakes began in Korea in 1905, and about one thousand events of mostly small magnitude, less than 4.0, have been detected to date in and near the peninsula. Strain release due to these earthquakes is almost negligible compared to that due to about 2186 historical earthquakes that occurred from 2 to 1904 A.D. in the peninsula. In this study, these historical earthquakes are cataloged from Korean historical documents, and their epicenters and intensities are estimated as best as possible. Temporal variations of the historical seismicity of Korea clearly reveal a very irregular strain release pattern over the nineteen centuries, with low to moderate seismicity most of the time except for the unusually high seismicity from the fifteenth to the eighteenth centuries. This highly irregular strain release pattern clearly indicates the characteristics of intraplate seismicity of the peninsula. Epicenters of large earthquakes appear to be well asso-ciated with the major faults and the boundaries of major geological units in the peninsula. It is to be noted that the major faults associated with large historical earthquakes were created by the Mesozoic tectonic activities that severely disrupted crustal layers of the peninsula. Historical earthquakes occurred all over the peninsula; however, the northeastern part appears relatively less seismic, probably due to the area being less disrupted during the Mesozoic. The b value in the magnitude– frequency relation determined from historical Korean earthquakes is 0.71, which is between those of the Japanese Islands and Eastern China and is lower than in many stable intraplate regions.
Abstract The Korean peninsula is widely regarded as being located at the relatively stable eastern margin of the Asian continent. However, more than 10 Quaternary faults have recently been discovered in and reported from the southeastern part of the Korean Peninsula. One of these, the Eupchon Fault, was discovered during the construction of a primary school, and it is located close to a nuclear power plant. To understand the nature and characteristics of the Quaternary Eupchon Fault, we carried out two trench surveys near the discovery site. The fault system includes one main reverse fault (N20°E/40°SE) with approximately 4 m displacement, and a series of branch faults, cutting unconsolidated Quaternary sediments. Structures in the fault system include synthetic and antithetic faults, hanging-wall anticlines, drag folds, back thrusts, pop-up structures, flat-ramp geometries and duplexes, which are very similar to those seen in thrust systems in consolidated rocks. In the upper part of the fault system, several tip damage zones are observed, indicating that the fault system propagates upward and terminates in the upper part of the section. Pebbles along the main fault plane show a preferred orientation of long axes, indicating the fault trace. The unconformity surface between the Quaternary deposits and the underlying Tertiary andesites or Cretaceous sedimentary rocks is displaced by this fault with a reverse movement sense. The stratigraphic relationship shows normal slip sense at the lower part of the section, indicating that the fault had a normal slip movement and was reversely reactivated during the Quaternary. The inferred length of the Quaternary thrust fault, based on the relationship between fault length and displacement, is 200–2000 m. The current maximum horizontal compressive stress direction in this area is generally east-northeast–west-southwest, which would be expected to produce oblique slip on the Eupchon Fault, with reverse and right-lateral strike-slip components.
Computational modelling frameworks for masonry bridges range from highly simplified methods to complex nonlinear finite element
or discrete elements. In majority of cases the macro level nonlinear finite element models1 and homogenisation techniques are adopted. Attention has also been given to assessment methodologies (discrete element method,
rigid block spring method, lattice modelling, discontinuous deformation analysis, combined discrete/finite elements), which
deal more directly with the discontinuous nature of structural masonry in a simplified micro modeling manner. These methods
model an inherently discontinuous medium, but are also applied to problems where the transition from a continuum to discontinuum
is important. Principal computational issue is the treatment of large number of distinct interacting domains, where the contact
conditions are continuously updated and enforced as the solution progresses. Modelling of masonry arches requires a consideration
of deformable multi-bodies and their contact nonlinearity, which is here realised in the context of the discontinuous deformation
analysis, based on an assumed deformation field within distinct domains of arbitrary shapes with a rigorous imposition of
contact constraints.
Along the southeastern coastline of the Korean peninsula, well-developed marine terraces are found at various elevations. The ages of these terraces, and the time of deposition of the terrace sediments are important to our understanding of the geological history of this area during the Quaternary period, and represent a unique record of the regional tectonic activity. Previous efforts to establish a chronology using optically stimulated luminescence (OSL) methods have produced controversial results, particularly because of stratigraphic inconsistency and poor reproducibility. In this paper, the application of OSL dating based on the single-aliquot regenerative-dose (SAR) protocol for quartz is investigated. The dependence of equivalent dose on the preheat and cut-heat temperatures (thermal treatment of the regeneration and test-doses, respectively) are examined. Linearly modulated luminescence signals from chemically cleaned quartz samples are used to identify the presence of a thermally unstable component with a large optical cross-section (component A′), which in part affects the ability to correct for sensitivity changes during measurements, and thus the reliability of the equivalent dose estimates. In some samples, a higher heat treatment after the test-dose is shown to improve our ability to measure a dose given in the laboratory before any heat treatment (dose recovery test). This higher temperature treatment effectively removes component A′, and hence improves sensitivity correction. Furthermore, the samples were broadly divided into poorly sorted and well-sorted, based on field evidence. The poorly sorted samples contain friable, weathered gravel clasts, which is a likely post-depositional source of quartz grains. In general, these grains will not have been zeroed prior to deposition, and so the poorly sorted samples are rejected from further age studies. Results obtained from the well-sorted samples are reproducible at each sampling location, and give ages grouping broadly into 50–70 and 110–120 ka, but laterally discontinuous on a scale of tens of km. Our OSL results for the younger group are supported by radiocarbon ages from overlying terrestrial deposits. It is concluded that these results point to considerable tectonic activity in the southeast of Korea during the Late Pleistocene.
Examination of damages affecting the buildings of the archaeological sites of Phaistos and Agia Triada (southern Crete) suggests that these Minoan settlements were probably destroyed by two major seismic events characterized by MKS intensities of IX–X and occurred at the end of the Protopalatial (1700 BC) and the Neopalatial (1450 BC) periods. Geological and morphological studies carried out in the neighbouring areas show the occurrence of E–W trending Quaternary normal fault segments (Spili and Agia Galini faults) that control the present topography and morphology, and exhibit steep young scarps mostly Holocene in age. These fault segments are related to a NW–SE extension direction, which is consistent with that indicated by the available focal mechanisms of the earthquakes occurring in this area in the last 50 years. Combining structural and seismic data we can infer that the Spili and Agia Galini fault segments could represent good candidates to be considered active faults generating large earthquakes (M≅6.5) that were responsible for the damages of Phaistos and Agia Triada. This hypothesis suggests that the Minoan palatial centres were destroyed by several large earthquakes related to ruptures along distinct fault segments rather than by a single catastrophic event that caused the abrupt destruction of the Minoan civilisation in the eastern Mediterranean.
This article examines the use of archaeological evidence for the assessment of historical earthquakes in the Eastern Mediterranean region and Middle East, long before the advent of modern seismology. We ask the questions when and where have large earthquakes happened in the past? How can this evidence contribute to our scientific understanding of earthquake activity? Is it possible on literary and archaeological grounds to distinguish between earthquake damage and damage from other causes? It is found that archaeological evidence for an earthquake is not always clear or unambiguous and that there is a need for collaboration between archaeologists, historians, geologists, engineering seismologists and workers in other disciplines, to evaluate the traces of earthquakes in excavations, both for understanding their effects at the site and for the information they can provide about the nature of the earthquake implicated.
Archaeological structures that exhibit seismogenic damage expand our knowledge of temporal and spatial distribution of earthquakes, afford independent examination of historical accounts, provide information on local earthquake intensities and enable the delineation of macroseismic zones. They also illustrate what might happen in future earthquakes. In order to recover this information, we should be able to distinguish earthquake damage from anthropogenic damage and from other natural processes of wear and tear. The present paper reviews several types of damage that can be attributed with high certainty to earthquakes and discusses associated caveats. In the rare cases, where faults intersect with archaeological sites, offset structures enable precise determination of sense and size of slip, and constrain its time. Among the characteristic off-fault damage types, I consider horizontal shifting of large building blocks, downward sliding of one or several blocks from masonry arches, collapse of heavy, stably-built walls, chipping of corners of building blocks, and aligned falling of walls and columns. Other damage features are less conclusive and require additional evidence, e.g., fractures that cut across several structures, leaning walls and columns, warps and bulges in walls. Circumstantial evidence for catastrophic earthquake-related destruction includes contemporaneous damage in many sites in the same area, absence of weapons or other anthropogenic damage, stratigraphic data on collapse of walls and ceilings onto floors and other living horizons and burial of valuable artifacts, as well as associated geological palaeoseismic phenomena such as liquefaction, land- and rock-slides, and fault ruptures. Additional support may be found in reliable historical accounts. Special care must be taken in order to avoid circular reasoning by maintaining the independence of data acquisition methods.
The long historical record of earthquakes, the physical effects on ancient building structures and the palaeoseismology provide a unique opportunity for an interdisciplinary tectonic analysis along a major plate boundary and a realistic evaluation of the seismic hazard assessment in the Middle East. We demonstrate with micro-topographic surveys and trenching that the Dead Sea fault (DSF) offsets left-laterally by 13.6±0.2 m a repeatedly fractured ancient Roman aqueduct (older than AD 70 and younger than AD 30). Carbon-14 dating of faulted young alluvial deposits documents the occurrence of three large earthquakes in the past 2000 years between AD 100 and 750, between AD 700 and 1030 and between AD 990 and 1210. Our study provides the timing of late Holocene earthquakes and constrains the 6.9±0.1 mm/yr slip rate of the Dead Sea transform fault in northwestern Syria along the Missyaf segment. The antepenultimate and most recent faulting events may be correlated with the AD 115 and AD 1170 large earthquakes for which we estimate Mw=7.3–7.5. The ∼830 yr of seismic quiescence along the Missyaf fault segment implies that a large earthquake is overdue and may result in a major catastrophe to the population centres of Syria and Lebanon.
In this paper, a simplified procedure for assessing the seismic capacity of masonry arches is proposed. The algorithm couples two quite simple analysis approaches, i.e. FEM linear analysis and limit analysis applied following Heyman’s hypotheses to a pre-chosen failure mechanism. In particular, linear analysis is used for detecting tensile and compressive stress zones in the masonry element and for identifying a probable class of failure mechanisms for which the collapse multiplier is then calculated taking advantage of a standard parametric CAD program. The procedure is iterative, since within the selected mechanism class, the position of the hinges has to be varied in order to minimise, in the kinematic approach, the collapse multiplier. The proposed simplified procedure is then applied to three triumphal arches of Neapolitan churches, verifying the results against non-linear FEM analysis using smeared cracking approach as implemented in the computer software ABAQUS. The three case studies considered in the paper are actually quite different in geometry. As a consequence, the structural behaviour and lateral strength are also expected to be fairly different. Despite the different geometry and the quite scattered values of lateral strength, a similar mechanism is identified for the three structural schemes. Also, the values of the lateral strength become closer when the total vertical load W is used for normalisation. This non-dimensional strength capacity can be directly compared to the seismic coefficient (non-dimensional strength demand), so that the results herein obtained can be useful for an evaluation of the seismic safety level of single structural macro-elements and, if their proper combination can be derived, of the church it belongs to.
On 11 March 2011, the Tohoku-oki earthquake in eastern Japan and the devastating tsunami that followed it caused severe damage and numerous deaths. To clarify the rupture process of the earthquake, we inverted teleseismic P-wave data applying a novel formulation that takes into account the uncertainty of Green's function, which has been a major error source in waveform inversion. The estimated seismic moment is 5.7 x 10^22 Nm (Mw = 9.1), associated with a fault rupture 440 km long and 180 km wide along the plate interface. The source process is characterized by asymmetric bilateral rupture propagation, but we also found continuous slips up-dip from the hypocenter, which led to a large maximum slip (50 m), long slip duration (90 s), and a large stress drop (20 MPa). The long slip duration, large stress drop, extensional (normal faulting) aftershocks in a previously compressional stress regime, and low-angle normal slips at approximately the depth of the plate interface suggest that the earthquake releas
Earth sciences in archaeology and history
- N N Ambraseys
Ambraseys, N.N., 1973, Earth sciences in archaeology and
history. Antiquity, 47, 229-230.
A paleoseismological study based on the damage characteristics of speleothems in limestone cave: a case study from Seongryu Cave in Uljin
- J.-H Choi
- K Ko
- J.-Y Kim
- Y.-S Kim
Choi, J.-H., Ko, K., Kim, J.-Y. and Kim, Y.-S., 2012, A paleoseismological study based on the damage characteristics of speleothems in limestone cave: a case study
from Seongryu Cave in Uljin, Korea. Journal of the
Geological Society of Korea, 48, 225-240 (in Korean
with English abstract).
The Geomorphic Characteristics of Bulguksa-region and the Earthquake Resistant Structure of the Bulguksa Temple
- S I Hwang
Hwang, S.I., 2007, The Geomorphic Characteristics of
Bulguksa-region and the Earthquake Resistant Structure
of the Bulguksa Temple. Journal of the Korean Geographical
Society, 42, 315-331 (in Korean with English abstract).