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In San Gregorio (L'Aquila, Italy) a three-story, reinforced concrete (RC) building had the first floor collapsed following the earthquake of April 6, 2009. The remaining two stories fell with a displacement in the horizontal projection of about 70 cm. This unusual behaviour is made more puzzling by the fact that buildings located at a short distanc...
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Context 1
... magnitude of the recorded earthquakes ranges between 3.0 and 4.0 Ml and the epicentral distance between 10 and 40 km. Table 1 reports the principal characteristics of these seismic events, while Fig. 10 reports the acceleration recordings of the strongest aftershock recorded, M = 4.0 on April 23rd at 15:14. The ambient noise recordings, 20-30 min long, have been acquired by a digital tri-direc- tional tromometer (Micromed Tromino), which is a high-resolution seismometer whose 24-bit dynamic is aimed at the very low amplitude range. ...
Context 2
... from the collapsed building the HVSR curves are flat as expected on outcropping well-cemented Miocene calcarenites. On the contrary, the HVSR curve close to the building (Fig. 11) shows Table 1, according with the technique proposed by Lermo and Chàvez-Garcìa (1993) and Castro et al. (1997). ...
Citations
... Therefore, there is a greater necessity of enhancing the study of the shallow sub-surface layers from Bucharest city and to create an even more detailed subsoil model which is necessary for the geophysical modelling of the underground and construction of microzonation, liquefaction potential and risk maps. Up to now, the preferred methodologies for underground investigation were based on seismic method, but examples from other regions (Boncio et al., 2011;Mucciarelli et al., 2011;Moscatelli et al., 2012) showed that the multi-methodologies approaches are bringing additional benefits in describing the geometry of geological layers and their geophysical parameters. ...
From a geological perspective, Bucharest city overlies on a thick cover of sedimentary deposits, that, until the present time, was directly investigated (by means of boreholes) only down to 3-3.3km. In the upper part, the unconsolidated sediments present a thickness increment from south-north, hostingphreatic and several confined aquifers (Figure 1). Therefore, any devised geo-model and zonation should consider the relatively frequent changes in each layer thickness, their inhomogeneity, and associated changes of geophysical parameters (density or in the shear-wave velocity), as well as the updated hydrogeological setting all over the city
... The reconstruction of this natural amplification occurring within the subsoil are of utmost importance in the Mirpur area in order to highlight the zones prone to high amplification. At a given site, an amplified frequency close to a building would lead to a resonance effect that increases the risk of structural damage (e.g., Mucciarelli and Monachesi, 1998;Mucciarelli et al., 2011). Hence, we performed HVSR surveys at five stations at site S3 adjacent to the collapsed and/or heavily damaged buildings in the Sang Kikri village. ...
The Mirpur area of Pakistan was severely damaged by extensive coseismic liquefaction following an earthquake of Mw 5.8 on 24 September 2019. Villages within 6 km of the epicenter were adversely affected due to extensive coseismic liquefaction-induced surface and shallow subsurface deformations. The earthquake affected all types of buildings and key infrastructure (e.g., the Upper Jhelum Canal and the main Jhelum–Jatlan road). Field observations and associated effects are presented, including horizontal-to-vertical spectral ratio (HVSR) data sets acquired from three sites to evaluate the site response characteristics of the liquefaction-affected soil profiles. As a result, rupture events strongly influenced spectral features (amplitude and frequency) and site-specific 1D shear-wave velocity profiles at sites S1 and S2. The dynamic behavior of HVSRs across ruptures at sites S1 and S2 corresponds to varied levels of seismic amplification, demonstrating the impact of liquefaction-induced ruptures of seismic origin on the site response that have not been reported previously in the literature. The consistent HVSR pattern of well-established high-frequency peaks at site S3 adjacent to partially damaged to completely collapsed buildings of different types further indicates the susceptibility of potential liquefaction hazard. These results agree with the surface liquefaction signatures in the field, revealed by inverted electrical resistivity tomography models in terms of liquified sand plugs, clay lenses and associated fractures, and increasing trends of radon concentration in the soil with decrease in the distance toward ruptures. Additionally, the successful application of HVSR as a cost-effective and speedy tool attests to the potential of the proposed approach in furnishing complementary information for better assessment of liquefaction hazards in the developing world, where financial constraints are a major issue. This can help with seismic hazard analysis and mitigation in the Mirpur area and may have applications in other seismically active regions of the world.
... The reconstruction of this natural amplification occurring within the subsoil are of utmost importance in the Mirpur area in order to highlight the zones prone to high amplification. At a given site, an amplified frequency close to a building would lead to a resonance effect that increases the risk of structural damage (e.g., Mucciarelli and Monachesi, 1998;Mucciarelli et al., 2011). Hence, we performed HVSR surveys at five stations at site S3 adjacent to the collapsed and/or heavily damaged buildings in the Sang Kikri village. ...
The Mirpur area of Pakistan was severely damaged by extensive coseismic liquefaction following an earthquake of M w 5.8 on 24 September 2019. Villages within 6 km of the epicenter were adversely affected due to extensive coseismic liquefaction-induced surface and shallow subsurface deformations. The earthquake affected all types of buildings and key infrastructure (e.g., the Upper Jhelum Canal and the main Jhelum–Jatlan road). Field observations and associated effects are presented, including horizontal-to-vertical spectral ratio (HVSR) data sets acquired from three sites to evaluate the site response characteristics of the liquefaction-affected soil profiles. As a result, rupture events strongly influenced spectral features (amplitude and frequency) and site-specific 1D shear-wave velocity profiles at sites S1 and S2. The dynamic behavior of HVSRs across ruptures at sites S1 and S2 corresponds to varied levels of seismic amplification, demonstrating the impact of liquefaction-induced ruptures of seismic origin on the site response that have not been reported previously in the literature. The consistent HVSR pattern of well-established high-frequency peaks at site S3 adjacent to partially damaged to completely collapsed buildings of different types further indicates the susceptibility of potential liquefaction hazard. These results agree with the surface liquefaction signatures in the field, revealed by inverted electrical resistivity tomography models in terms of liquified sand plugs, clay lenses and associated fractures, and increasing trends of radon concentration in the soil with decrease in the distance toward ruptures. Additionally, the successful application of HVSR as a cost-effective and speedy tool attests to the potential of the proposed approach in furnishing complementary information for better assessment of liquefaction hazards in the developing world, where financial constraints are a major issue. This can help with seismic hazard analysis and mitigation in the Mirpur area and may have applications in other seismically active regions of the world.
... It can arise during seismic events when the oscillation frequency of a building is very close to that of the foundation soil, causing an increase in damage [32][33][34][35]. The soil-building interaction effect for a single/limited number of closed-spaced buildings has been numerically and experimentally studied [36][37][38][39], while for the urban scale as a whole only numerical simulation approaches have been proposed [33,[40][41][42][43][44][45][46]. Recently, Agea-Medina et al. (2020) [47] evaluated the probability of resonance effect in several districts of municipalities of Alicante and Elche, while other authors have produced soil-building resonance level maps based on numerical relations provided by seismic regulations [48,49], and on extensive collections of experimental data [8]. ...
In the context of seismic risk, studying the characteristics of urban soils and of the built environment means adopting a holistic vision of the city, taking a step forward compared to the current microzonation approach. Based on this principle, CLARA WebGIS aims to collect, organize, and disseminate the available information on soils and buildings in the urban area of Matera. The geodatabase is populated with (i) 488 downloadable geological, geotechnical, and geophysical surveys; (ii) geological, geomorphological, and seismic homogeneous microzone maps; and (iii) a new Digital Surface Model. The CLARA WebGIS is the first publicly available database that reports for the whole urban area the spatial distribution of the fundamental frequencies for soils and the overlying 4043 buildings, along with probability levels of soil-building resonance. The WebGIS is aimed at a broad range of end users (local government, engineers, geologists, etc.) as a support to the implementation of seismic risk mitigation strategies in terms of urban planning, seismic retrofitting, and management of post-earthquake crises. We recommend that the database be managed by local administrators, who would also have the task of deciding on future developments and continuous updating as new data becomes available.
... It can arise during seismic events when the oscillation frequency of a building is very close to that of the foundation soil, causing an increase in damage [32][33][34][35]. The soilbuilding interaction effect for a single/limited number of closed-spaced buildings has been numerically and experimentally studied [36][37][38][39], while for the urban scale as a whole only numerical simulation approaches have been proposed [33,[40][41][42][43][44][45][46]. Recently, Agea-Medina et al. (2020) [47] evaluated the probability of resonance effect in several districts of municipalities of Alicante and Elche, while other authors have produced soil-building resonance level maps based on numerical relations provided by seismic regulations [48,49], and on extensive collections of experimental data [8]. ...
... Engineering Geology 272 (2020) 105647 (Tertulliani, 1999), (Sanchez-Sesma, 1987), (Paolucci, 2002), (Massa et al., 2014), (González et al., 2004), (Panzera et al., 2018), , (Tertulliani and Maramai, 1998), , and are nowadays explicitly taken into account, through simplified approaches, in the most advanced Codes for the definition of the design seismic demand (Mahajan, 2009). As for the Italian earthquakes, site amplification effects were recognized as one of the main causes of the observed damage pattern on several urban centers (Strollo et al., 2007), (Mucciarelli et al., 2011). Focusing the attention on the 2016 Central Italy earthquake, the relation between site effects and damage patterns was stressed out by Sextos et al. (Sextos et al., 2018), who combined traditional reconnaissance methods with advanced imaging and damage detection routines enabled by information and communications technologies (ICT) and geomatics approaches. ...
The great influence of site effects on damage patterns produced by seismic events of the past, stresses out the need to find proper relationships between the site local conditions and the potential damage that existing buildings may experience under earthquakes of different intensity.
This issue proved to be relevant, especially for those masonry buildings in small historic centers, such as the ones belonging to the Apennine areas of Italy that suffered serious damage after the 2009 L'Aquila and the 2016–2017 Central Italy seismic sequences. Some of these centers showed a not regular damage distribution, suggesting that site effects influenced the seismic response of their buildings.
In this perspective, this paper provides an attempt to correlate earthquake damage to site effects, focusing the attention on two historic centers of the Abruzzi region, Campotosto and Cortino, which were damaged by the 2016–2017 Central Italy seismic sequences and for which the amplification factors of the subsoil were carefully identified, resulting more influencing were higher damage was observed.
First, the damage patterns observed after the 18 January 2017 seismic shock are represented in terms of Damage Probability Matrices and maps developed in GIS environment. Moreover, the data collected in terms of stats are interpreted through the application of the binomial probability distribution, in order to check its reliability in reproducing the gathered frequencies.
Finally, in order to justify the damage of some specific buildings, the results of site response analyses are compared with the damage observed punctually on three damaged masonry buildings.
... With the aim of investigating the deep structure of the BMSL (depth of the sliding surface, deep tectonic structures influencing landslide evolution, etc.), ERT survey was carried out. In recent years, this technique has been increasingly applied in seismotectonic and geomorphological studies (Giocoli et al. 2008;Balasco et al. 2011), to investigate the geological and structural setting (Giocoli et al. 2015) and to study landslides , ERT is a fast, non-invasive and low-cost geophysical method, widely applied to obtain high-resolution 2-D images of the subsurface resistivity pattern (Mucciarelli et al. 2011;Moscatelli et al. 2014;Stabile et al. 2014). The ERT surveys were performed along four profiles by means of a Syscal R2 (Iris Instruments) resistivity metre, coupled with a multielectrode acquisition system (36, 44 or 48 electrodes). ...
The Brindisi di Montagna Scalo Landslide in Southern Italy is an active complex mass movement, which affects the left slope of the Basento River. In the last few decades, this landslide has been continuously monitored, as it directly threatened some of the most important communication routes in the Basilicata Region. Nevertheless, little progresses have been made to prevent further landslide advancement, and continuous maintenance is required. With the aims of better understanding, the main factors controlling the evolution of this landslide, and suggesting the most appropriate countermeasures, a multidisciplinary study, based on the integration of direct and indirect techniques, was carried out. Direct techniques included multi-temporal geomorphological analysis of the slope, alongside geological and structural field observations. Indirect techniques consisted of electrical resistivity tomography acquisition. The combined analyses of the geological and geophysical data showed that Quaternary tectonic processes played a fundamental role as a predisposing factor, whereas seasonal rainfall, and the perpetual undercutting by erosional processes caused by the Basento River at the toe of the landslide are the main triggering mechanisms. The Brindisi di Montagna Scalo Landslide represents an outstanding case-study, concerning the interaction between a flow-like complex landslide and essential linear infrastructure, such as motorways and railways.
... Low quality of construction materials is one of the reasons for structural damage, as has been reported after past earthquakes [8,29,37,38]. Uncontrolled quality for concrete mixed on-site, non-standard size of aggregates and use of water from rivers to prepare the mortar are among the factors that lead to low compressive strength of concrete in the structural element. Design codes recommend 20 MPa [21] to 21 MPa [23] as the minimum compressive strength of concrete in a structural element. ...
This paper discusses the outcome of an investigation which was conducted soon after the 2015 Sabah earthquake in Malaysia. Buildings in the affected area were mainly constructed from reinforced concrete (RC) and wooden materials. Although the Mw 6.0 earthquake imposed significant damage to the majority of RC buildings, no significant structural damage was observed for the wooden structures. It was found that damage to the RC buildings was mainly because of non-ductile detailing of the structural components, strong-beam weak-column condition, captive-column and short-column effects, soft and weak stories mechanism, irregularity in plan and elevation, unconfined gable/infill walls, bad workmanship, and the low quality of construction materials. It was observed that many wooden structures had flaws in their design and construction as well. However, because of the high strength-to-weight ratio and the flexible properties of wooden materials which allow them to undergo several cycles of deformation without breaking, they survived the seismic actions. This paper identifies and discusses the main reasons for the damage observed in RC buildings and the construction flaws that were observed for wooden structures. Recommendations from seismic design codes in order to prevent the occurrence of such damage in the future are also highlighted.
... Thanks to the diverse range of now mature exploration methodologies, applied geophysics holds a great potential for the collection of spatially distributed data that can be both combined with each other and with data derived from direct surveys. Geophysical methods have been applied in environmental and engineering studies with the aim to locate and characterize near-surface geological structures Giocoli et al. 2007;Galli et al. 2017), aquifers (Vereecken et al. 2006), landfills (Konstantaki et al. 2015), landslides (Jongmans and Garambois 2007;Perrone et al. 2014), liquefaction phenomena (Giocoli et al. 2014), to investigate site for building foundations (Soupios et al. 2007), to locate underground excavations (Kova cevi c et al. 2013), to evaluate earthquake hazard and to support seismic microzonation studies (Boncio et al. 2011;Gallipoli et al. 2011;Mucciarelli et al. 2011;Vignola et al. 2018). ...
... The basic feature of ambient vibration measurements has been providing a fast and cheap prospecting tool useful to supply subsoil information. Having to perform measurements in urban environment, we have used fast and non-invasive approaches: single-station seismic ambient noise measurements (Mucciarelli 1998; Ch avez-Garcı a and C ardenas 2002; Gallipoli et al. 2004;Mucciarelli et al. 2011), earthquakes recordings (HVSR, Castro et al. 1998;Di Giulio et al. 2005;Gallipoli et al. 2014) and noise array measurements (Okada 2003). The joint use of single-station and multi-station ambient vibration measurements could provide important contribution to the development of a reliable geological model of the area of interest and to feed numerical procedures devoted to the assessment of seismic response (Bard 1999). ...
A geophysical approach, based on the integration of satellite differential interferometric SAR technique and in situ geoelectrical and seismic methods, was applied with the aim to characterize a portion of urban area of Avigliano (PZ) town in Basilicata Region (southern Italy) affected by ground instability phenomena. Satellite analysis helped to discriminate areas of the town affected by superficial deformations and to monitor the dynamic behaviour of the structures located in these areas. Results from geoelectrical and seismic (active and passive) methods were compared with direct data (stratigraphic) and were interpreted with the aim to reconstruct the geometry of the subsoil. The joint application of both in situ techniques allowed the overcoming of the specific limits of each method and to improve the poor quality of the data due to the noise conditions typical of measurements carried out in urban areas. A preliminary geophysical model of the subsoil was obtained. The geophysical contrasts highlighted the presence of lithological discontinuities due to the superficial deformation processes that are affecting the portion of the investigated urban area. All the information has been transferred to the public administration technicians involved in the mitigation of hydrogeological risk in Basilicata Region.
... Research outcomes suggest that the nature and complexity of the local site conditions and/or the soil-structure resonance phenomena are capable of increasing structural damage [1][2][3][4][5][6]. It is also welldocumented that, during strong motion excitations, various building typologies and structural elements have avoided damage or suffered multi-level damage [7,8]. ...
... Resonance evaluation has been used to study the damage pattern caused by earthquake events [11][12][13]. During the L'Aquila earthquake, a building collapsed at a site located close to a strong discontinuity, while buildings located a short distance away suffered little or no damage [4]. A recent example in [6] highlights the importance of local site effects in earthquake damage distribution after the Emilia earthquake, where two identical tall reinforced structure (RC) structures located at a close distance suffered different damage. ...
... The authors in [17,18] applied the Horizontal to Vertical Spectral Ratio (HVSR) to determine the dynamic characteristics of the Tower of Pisa and to identify vulnerable points of the Roman coliseum. Since this pioneering work of Nakamura [17][18][19][20], the HVSR technique using either microtremor or earthquake data has been applied in several studies to estimate a building's fundamental frequency of vibration and soil-structure interaction phenomena [4,14,16,[21][22][23][24][25][26]. The advantage of microtremors is that they can be used for a preliminary estimation of a building's vulnerability without the need for structural details (the width of frames, the number of openings, the mass of floors, and the number of columns). ...
Monitoring seismic structural response is an essential issue in earthquake risk assessments and mitigation studies for monumental buildings in order to undertake earthquake disaster management. This study aims at identifying the resonant frequency of soil and modern and historical buildings in three major municipalities of Crete (Heraklion, Chania, and Rethymno) using ambient noise recordings (microtremors) considering the importance of soil–structure interaction to seismic structural response, particularly for historical buildings and monumental structures. In this study, ambient noise recordings have been processed through Horizontal to Vertical Spectral Ratios (H/V) to preliminarily examine the main frequencies and to examine whether the building has its main frequency close to that of the soil in order to identify potential resonance phenomena. Numerous ambient noise recordings were recorded on the soil, in the basement, and at each n-floor of the buildings. The incorporation of local site conditions and soil-building resonance phenomena into the urban planning development of Crete regarding earthquake risk assessments is necessary. In this direction, microtremors can be used as an effective tool to support civil protection preparation and operational decision-making in terms of earthquake disaster, specifically in the area of Crete, which is characterized by high seismic activity and a high cultural monuments capacity.
