A new paper from Dr. Tom Rockwell and others present evidence for eight events that pre-date the 1202 and 1759 C.E. for the Dead Sea Transform Fault. In the past 2000 years, they observe evidence for a total of 10 surface-rupturing earthquakes, of which seven or eight events occurred in the first millennium, compared to just two in the second millennium. Results suggest the most of the Dead Sea Transform Fault has remained locked since the last large rupture in 1202 and is accumulating elastic strain. Therefore, it is imperative to prepare for a large earthquake, which will occur sooner or later.
A Paleoseismic Record of Earthquakes for the Dead Sea Transform Fault between the First and Seventh Centuries C.E.: Nonperiodic Behavior of a Plate Boundary Fault
Neta Wechslera, Thomas K. Rockwellb, Yann Klingerc, Petra Štěpančíkovád, Mor Kanaria, Shmuel Marcoa, and Amotz Agnone
aDepartment of Geophysical, Atmospheric, and Planetary Sciences, Tel Aviv University, Tel Aviv 69978, Israel
bDepartment of Geological Sciences, 5500 Campanile Dr., San Diego State University, San Diego, California 92182
cEquipe de Tectonique, Institut de Physique du Globe de Paris, 1, rue Jussieu, 75238 Paris, France
dInstitute of Rock Structure and Mechanics, Academy of Science Czech Republic, v.v.i. V Holesovickach 41, 182 09 Prague 8, Czech Republic
eInstitute of Earth Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel
We present new results from a paleoseismic trenching campaign at a site across the Jordan Gorge Fault (JGF), the primary strand of the Dead Sea Transform in northern Israel. In addition to the previously recognized earthquakes of 1202 and 1759 C.E., we observe evidence for eight surface-rupturing earthquakes prior to the second millennium C.E. The past millennium appears deficient in strain release with the occurrence of only two large ruptures, when compared with the preceding 1200 years. Assuming Gutenberg–Richter magnitude–frequency distribution, there is a discrepancy between measured rate of small-magnitude earthquakes (M <4) from instrumental records and large earthquake rates from paleoseismic records. The interevent time of surface-rupturing earthquakes varies by a factor of two to four during the past 2 ka at our site, and the fault’s behavior is not time predictable. The JGF may be capable of rupturing in conjunction with both of its southern and northern neighboring segments, and there is tentative evidence that earthquakes nucleating in the Jordan Valley (e.g., the 749 C.E. earthquake) could either rupture through the stepover between the faults or trigger a smaller event on the JGF. We offer a model of earthquake production for this segment in which the long-term slip rate remains constant while differing earthquake sizes can occur, depending on the segment from which they originated and the time since the last large event. The rate of earthquake occurrence in this model does not produce a time-predictable pattern over a period of 2 ka as a result of the interplay between fault segments to the south and north of the JGF.
N Wechsler, TK Rockwell, Y Klinger, P Štěpančíková, M Kanari, S Marco, and A Agnon, A Paleoseismic Record of Earthquakes for the Dead Sea Transform Fault between the First and Seventh Centuries C.E.: Nonperiodic Behavior of a Plate Boundary Fault, Bulletin of the Seismological Society of America, Vol. 104, No. 3, pp. –, June 2014, doi: 10.1785/0120130304