Atlas: Archaeoseismic studies reveal patterns of earthquake reccurrence during the last two millennia in the Dead Sea Transform by Shmulik Marco

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Archaeoseismic studies reveal patterns of earthquake reccurrence during the last two millennia in the Dead Sea Transform
by
Shmulik Marco
Department of Geophysics and Planetary Sciences, Tel Aviv University, Tel Aviv, Israel
Coauthors: Amotz Agnon and Ronnie Ellenblum, The Hebrew University of Jerusalem, Israel; Thomas Rockwell, San Diego State University, California

Our archaeoseismological and geological findings corroborate the analyses of reported earthquake damage in the Middle East. In particular the historical data on the earthquakes of AD749, 1202, and 1759, which ruptured sections of the Dead Sea Transform are confirmed by on-fault and off-fault paleoseismic and archaeoseismic studies. The observed ruptures in these earthquakes coincide with the reported zones of maximum damage. Assuming that similar reliability can be attributed to other historical sources we use them to estimate the rupture locations of earthquakes of the last two millennia in the northern DST. Three types of earthquake reccurrence patterns are noticeable. First, a quasi-periodic recurrence of earthquakes that span the ~100-km-fault segment between the Dead Sea and the Sea of Galilee, starting with the 31 BC earthquake and continuing with the AD 363, 749, and 1034. Two smaller earthquakes of 1546 and 1927 followed, altogether exhibiting a mean recurrence interval of 390±80 years. This pattern is not observed elsewhere along the Dead Sea Fault. The second observed pattern is a sequence of north-to-south progressive fault ruptures that occurred once in 859, 991, 1033, and possibly 1068, and again beginning in 1157 in the north, followed by 1170, 1202, and 1293 further south. No similar patterns, neither before nor after these two series are observed. The third type is temporal clustering, which is apparent in various time windows throughout the record. One case of a double event, when two earthquakes ruptured a continuous section first on October 30 and second on November 25, 1759, appears to be exceptional. The quasi-periodic and sequential failure patterns appear to last but short periods, of the order of several decades to a few centuries. Our interpretation also shows that it has now been eight centuries since most of the Dead Sea Fault in Israel sustained significant strong earthquake rupture, similar to Meghraoui et al.’s (2003) finding in northern Lebanon and Syria.

Date received: May 4, 2004