Tri-Millennial History of Earthquake Offsets of Tell Ateret on the Dead Sea Fault: a perfect time-predictable behavior?
Abstract
The abundance of archaeological sites and historical documentation along the Dead Sea Fault (DSF) enables a higher resolution for dating of a tectonically active region. The site of Ateret (Jordan Gorge, north Israel), settled since Stone Age, displays abundant well dated walls that were repeatedly offset since the Early Bronze Age to 1759AD. The dated ruptures enable a kinematic reconstruction of this plate boundary, separating between the Arabia and the Sinai tectonic-plates. We have recently unearthed three consecutive offsets that supplement our published data to constrain a five-event catalogue spanning three millennia. The new catalog, totaling five events, sheds light on the distribution of slip in time and space. The archaeologic slip-rate obtained for the last 3 kyr is in perfect agreement with the 5 kyr value known form paleoseismic trenching. The average slip rate, 3 mm/yr, is ~60% of the GPS determined relative plate velocity. The discrepancy between the archaeologically measured slip and the GPS determined velocity is accommodated by diffuse off-fault deformation and possibly by elasticity. Examining the size distribution of detected slip events indicates that a uniform slip model is not compatible with the Jordan Gorge earthquake history: the largest/smallest slip ratio is ≥5. The complexity apparent in the catalog seems to stem from the nearby branching of the plate boundary, as suggested from the two latest events of 1202 AD and 1759 AD, each ruptured a different branch. The archaeologic data supplemented by allegedly dubious historical catalogs generate a perfect time-predictable model for three thousand years ending in the 1950’s. At that time we should have seen an earthquake rupture whilst the instrumental catalog is devoid of such an event. The 1837 AD M7 rupture of a yet smaller branch of the fault can explain the deviation from the model, highlighting the role of branching in generating complex behavior. Slip history at Tel Ateret archaeological site. Three of the five events are constrained in time by archaeology and history; for two events we selected the time of a known historic earthquake.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.T33B2237M
- Keywords:
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- 7230 SEISMOLOGY / Seismicity and tectonics;
- 7250 SEISMOLOGY / Transform faults;
- 8111 TECTONOPHYSICS / Continental tectonics: strike-slip and transform;
- 8123 TECTONOPHYSICS / Dynamics: seismotectonics