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Sedimentary basins are prominent structures along the Dead Sea Transform. Over the years, they have been intensively studied, raising several fundamental questions about their evolution. The northern Gulf of Elat/Aqaba (GEA) basin is located between the deep marine basins of the GEA and the shallow onland basins of the Arava Valley. The definitions...
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Citations
... Previous studies of the submarine structure of the Northern Gulf of Aqaba-Elat (NGAE) suggest slip on the east and west boundary faults is predominantly normal and recently active (Ben-Avraham, 1985;Ben-Avraham et al., 1979;Ben-Avraham and Tibor, 1993). However, recent high-resolution seismic and bathymetric data (Tibor et al., 2010;Hartman, 2012;Hartman, 2015) revealed a complex fault system across the shelf of the NGAE with varying degrees of recent seismic activity. Hartman et al. (2015) conclude that during the Holocene, the submarine Avrona Fault (Evrona Fault in some papers) accommodates most of the strike-slip faulting in this transform plate boundary, between the Sinai sub-plate and the Arabian plate, with an average sinistral slip-rate of 0.7±0.3 ...
... Additionally, we try to augment the paleoseismic record of the region, using field evidence for past earthquakes on-and off-shore. We integrated newly suggested offshore fault location (Hartman, 2012), analysis of aerial photos from 1945, and Ground Penetrating Radar (GPR) survey to hypothesize the fault location for paleoseismic trenching site selection. Trenching revealed the fault and associated liquefaction features. ...
Located at the Northern tip of the Gulf of Aqaba-Elat, the on-land continuation of the submarine Avrona Fault underlies the Hotels District of Elat, where seismic deformation was documented after the 1995 Nuweiba (Sinai) earthquake (7.2 Mw). This active segment of the Dead Sea Fault is the transition between the deep marine basin of the Gulf and the shallow continental basin of the Arava Valley. Paleoseismic trenching revealed the fault, based on surface rupture and liquefaction features. Radiocarbon dating of the offset strata and liquefaction suggest that it ruptured in the historical earthquakes of 1068 and 1458 AD, yielding a vertical slip rate of ~1.1 mm/yr. Independent dating of anomalous coarse grain events in core sediments from offshore nearby suggests these earthquakes triggered marine sediment mass-flow. Using this pattern, we analyze anomalous coarse grain events in several cores to compile a paleoseismic record dating back to the late Pleistocene.
... North of the GEA, the DST passes along the Arava (Wadi 'Arabah) Valley. Mapping of offset surface features, aided by field observations, aerial photo analysis, and paleoseismic trenches [e.g., Zak and Freund, 1966;Garfunkel et al., 1981;Ginat et al., 1998;Klinger et al., 2000aKlinger et al., , 2000bNiemi et al., 2001;Le Béon et al., 2010, 2012 and recent gravimetric and magnetic studies [Haberland et al., 2007;ten Brink et al., 2007] revealed that the DST traverses the central Arava Valley predominantly as a single, almost continuous, sinistral strike-slip fault. Modeling of gravity and magnetic data [ten Brink et al., 1999[ten Brink et al., , 2007, and seismic profiles [Frieslander, 2000] [1985]). ...
... (2) underwater observations made by divers on two such structures exposed at the seafloor at depths of 20 m and~60 m revealed the presence of fossil coral that in several locations are covered with live corals, sponges, and seaweed [Makovsky et al., 2008;Hartman, 2012], and (3) these structures are long, narrow, and have relatively flat tops similar to the fringing reefs that develop along coasts in close proximity to the sea surface today. All these characteristics suggest that the mounded structures represent relict fringing coral reefs (Table 1). ...
... The sequence packages are further divided into seismic units (U0-U9). Reef systems (R1-R6) situated within the stratigraphic units are interpreted as well [Hartman, 2012]. Figure 5 correlates the GEA seismic sequence boundaries to eustatic changes in sea level. ...
The northern Gulf of Elat/Aqaba is located in the transition between the deep marine basins of
the gulf and the shallow onland basins of the Arava Valley. Interpretation of 500 km of high-resolution seismic
reflection data collected across the northern shelf reveals the tectonic structure and evolution of this
transition. Six NNE-trending faults and one E-W trending transverse fault are mapped. Slip rates are calculated
based on measured offsets and age determination based on a radiocarbon-calibrated sedimentation rate and
a Quaternary age model. The most active fault is the Evrona Fault that absorbs most of the left lateral slip
within the basin with an average sinistral slip rate of 0.7 ± 0.3 mm/yr through the Late Pleistocene and
2.3–3.4 mm/yr during the Holocene. Two intrabasin faults east of the Evrona Fault that have been inactive for
the last several tens of thousands of years were mapped, and motion from these faults has likely transferred
to the Evrona Fault. The basin is flanked on the west by the Elat Fault and on the east by the Aqaba Fault. Both
faults are marked by large bathymetric escarpments. Based on displaced seismic reflectors, we calculate a
Holocene vertical slip rate of 1.0 ± 0.2 and 0.4 ± 0.1 mm/yr for the Elat and Aqaba Faults, respectively. The
geometry, slip rates, and slip history of the northern Gulf of Elat/Aqaba faults show that during the Late
Pleistocene several intrabasin faults became dominant across the basin but that during the Holocene the
Evrona Fault accommodates most of the strike slip.
... Hartman (2012) calculated a Holocene, vertical slip rate of 1Á0 AE 0Á2 mm yr À1 and 0Á4 AE 0Á1 mm yr À1 for the Elat and Aqaba faults that bound the basin on its west and east, respectively. The strike-slip Evrona fault was traced in the eastern Elat Subbasin (Makovsky et al., 2008;Hartman, 2012;Hartman et al., 2014). Makovsky et al. (2008) suggested ca 30 m of sinistral slip and ca 10 m of normal offset between the Ayla High and the Elat Sub-basin during the Holocene, resulting in an average relative subsidence rate of ca 1 mm yr À1 of the Elat Sub-basin. ...
... Other relict reefs in the northern GEA can only be used as a relative marker, not as absolute elevation, for highstands and stillstands of sea-level. Because the R4 reef west of the Evrona is vertically offset the same as the R5 reef, it also implies that the subsidence rate is highly variable (Hartman, 2012). ...
Quaternary reef development and demise have been shown to correspond to worldwide sea-level fluctuations and related environmental changes, yet the mechanisms and rates affecting this relationship are not well resolved. A set of high-resolution seismic reflection and multibeam bathymetric data was interpreted. Six distinct systems of relict fringing reefs embedded within the sedimentary cover of the northern shelf of the Gulf of Elat/Aqaba were identified. The two uppermost relict fringing reefs are also exposed on the sea floor in water depths of ca 20 m and ca 60 m, along the north-western corner of the northern Gulf of Elat/Aqaba and sub-parallel to the current northern coast, respectively. Two other relict fringing reefs are laterally correlated to each of the last two transgressive cycles, and are inferred to have formed during decelerations in sea-level rise during the last two deglaciations. These reefs and the units to which they are laterally correlated portray a repeating stratigraphic pattern of reef development during deposition of seismically homogeneous sediment and an ensuing demise during deposition of heterogeneous sediment. Correlation of the reef stratigraphy with rates of Late Quaternary sea-level rise and a sediment accumulation rate from one shelf core provide age estimations for the seismic stratigraphy. Two phases of fringing reef generation occurred during the last deglaciation (since ca 18 ka); the older reef probably developed between 12.8 and 11.5 ka at ca 60 m below present sea-level (m bpsl) and the younger reef after 8.4 to 8 ka at ca 20 m bpsl. These last two phases of reef generation are separated by a lobate seismic unit that is interpreted as fluvial-deltaic deposits that backstepped across the shelf during the Early Holocene transgression. Results suggest that fringing reefs evolved along the northern shelf of the Gulf of Elat/Aqaba only during relative decelerations in sea-level rise, contemporaneous with low input of terrigenous sediment and probably during a period of aridity. At present, no fringing reef grows along the northern coast of the Gulf of Elat/Aqaba, suggesting that these relatively arid periods may have been drier than Recent. The pattern of slowdown in sea-level rise contemporaneous with conditions of increased aridity seems to have repeated during the last two sea-level rises, approximately at the same sea-levels, suggesting a common mechanism of short (millennium-scale) phases of eustatic and climatic alteration during deglaciations.This article is protected by copyright. All rights reserved.
... (2012) calculated a Holocene, vertical slip rate of 1Á0 AE 0Á2 mm yr À1 and 0Á4 AE 0Á1 mm yr À1 for the Elat and Aqaba faults that bound the basin on its west and east, respectively. The strike-slip Evrona fault was traced in the eastern Elat Subbasin (Makovsky et al., 2008; Hartman, 2012; Hartman et al., 2014). Makovsky et al. (2008) suggested ca 30 m of sinistral slip and ca 10 m of normal offset between the Ayla High and the Elat Sub-basin during the Holocene, resulting in an average relative subsidence rate of ca 1 mm yr À1 of the Elat Sub-basin. ...
... Other relict reefs in the northern GEA can only be used as a relative marker, not as absolute elevation, for highstands and stillstands of sea-level. Because the R4 reef west of the Evrona is vertically offset the same as the R5 reef, it also implies that the subsidence rate is highly variable (Hartman, 2012). The interpreted transgression phases of U1 and U2 and reefs R1 and R2 were correlated to the sea-level rise before Marine Isotope Stages (MIS) 9 and 7 (Shackleton & Opdyke, 1973; Siddall et al., 2003), respectively (Fig. 10). ...
The northern shelf of the Gulf of Eilat/Aqaba (GEA) is an ideal location for the study of fringing reef generation and mortality in response to changes in sedimentation and sea level. It is an oligotrophic marine environment surrounded by an arid region with a limited supply of sediments, and continued growth of fringing reefs. In this study we investigate the history of coral growth and mortality in the area based on high resolution geophysical data including seismic, multibeam, sidescan sonar and underwater direct observations and sampling. Investigating the morphology of the seafloor reveals two ancient fringing reefs at water depths of ~20 meters and ~65 meters. The ~20 meters fringing reef is located along the northwestern corner of the northern GEA and the ~65 meters reef is sub-parallel to the entire current northern coast. The interpretation of the seismic profiles shows a total of six sequences of reef generation, including the two ancient fringing reefs that are exposed on the seafloor. While the three deeper reef sequences are hard to correlate laterally in the seismic data, the upper three reef structures are visible and were spatially traced as long (>1 km) and narrow (
