A 220,000-year-long continuous large earthquake record on a slow-slipping plate boundary

Abstract

Large earthquakes (magnitude ≥ 7.0) are rare, especially along slow-slipping plate boundaries. Lack of large earthquakes in the instrumental record enlarges uncertainty of the recurrence time; the recurrence of large earthquakes is generally determined by extrapolation according to a magnitude-frequency relation. We enhance the seismological catalog of the Dead Sea Fault Zone by including a 220,000-year-long continuous large earthquake record based on seismites from the Dead Sea center. We constrain seismic shaking intensities via computational fluid dynamics modeling and invert them for earthquake magnitude. Our analysis shows that the recurrence time of large earthquakes follows a power-law distribution, with a mean of 1400 ± 160 years. This mean recurrence is notable shorter than the previous estimate of 11,000 years for the past 40,000 years. Our unique record confirms a clustered earthquake recurrence pattern and a group-fault temporal clustering model, and reveals an unexpectedly high seismicity rate on a slow-slipping plate boundary.

A New Approach to Constrain the Seismic Origin for Prehistoric Turbidites as Applied to the Dead Sea Basin

“…Moreover, based on numerical simulation of the in situ deformation processes and its application to Core 5017‐1, Lu et al. (2020b) revealed and quantified the history of large earthquakes along the central Dead Sea Fault over the past 220 kyr.…”

“…Widespread in situ soft‐sediment deformation characterizes the Dead Sea sediments (Marco & Agnon, 1995; Lu et al., 2017b; Alsop et al., 2019), which manifests as several forms of (i) linear waves, (ii) asymmetric billows, (iii) coherent vortices, and (iv) intraclast breccias (Figures 1d–1m) (Lu et al., 2020b). The temporal correspondence of these structures with historic earthquakes (Ken‐Tor et al., 2001; Migowski et al., 2004) and their juxtaposition against syn‐depositional faults (Marco & Agnon, 1995) reveal that these deformations are seismites.…”

“…This situation is recorded from the lake margin and has been used to reconstruct the earthquake history of the Dead Sea Fault over the last 70 kyr (Ken-Tor et al, 2001;Marco et al, 1996;Migowski et al, 2004). Moreover, based on numerical simulation of the in situ deformation processes and its application to Core 5017-1, Lu et al (2020b) revealed and quantified the history of large earthquakes along the central Dead Sea Fault over the past 220 kyr. Scenario II involves sandy turbidite overlying an in situ seismite, while scenario III encompasses Type II turbidite overlying an in situ seismite.…”

“…The sedimentary sequence comprises alternating laminae of aragonite and detritus (aad; Text S1) (Figure 1o), homogeneous mud (Figures 1n and 1o), gypsum (Figure 1b), halite (Figure 1c) (Neugebauer et al, 2014;Lu et al, 2017aLu et al, , 2020a, and seismically disturbed units (Figures 1d-1m) (Lu et al, 2017b(Lu et al, , 2020b. The first four types of sediment are regarded as background sedimentation (Text S2), while disturbed units including soft-sediment deformation, liquefied sand layers, slumps, chaotic deposits, and micro-faults have been interpreted as seismites (Heifetz et al, 2005;Ken-Tor et al, 2001;Lu et al, 2017bLu et al, , 2020bMarco & Agnon, 1995;Wetzler et al, 2010 (Bartov et al, 2006;Ben-Avraham et al, 2008) Widespread in situ soft-sediment deformation characterizes the Dead Sea sediments (Marco & Agnon, 1995;Lu et al, 2017b;Alsop et al, 2019), which manifests as several forms of (i) linear waves, (ii) asymmetric billows, (iii) coherent vortices, and (iv) intraclast breccias (Figures 1d-1m) (Lu et al, 2020b). The temporal correspondence of these structures with historic earthquakes (Ken-Tor et al, 2001;Migowski et al, 2004) and their juxtaposition against syn-depositional faults (Marco & Agnon, 1995) reveal that these deformations are seismites.…”

“… Tectonic setting of the Dead Sea Basin (a) and chemical data characterizing in situ seismites (d–m) (Lu et al., 2020b) and background deposits (b‐c, n‐o) in Core 5017‐1. (a) Active faults in the basin (Bartov et al., 2006; Ben‐Avraham et al., 2008).…”