HR: 11:05h
AN: T42B-04    [Abstracts]
TI: Active Thrusting Offshore Mount Lebanon: Source of the Tsunamigenic A.D. 551 Beirut-Tripoli Earthquake
AU: * Tapponnier, P
EM: tappon@ipgp.jussieu.fr
AF: IPGP - Tectonique, 4 place Jussieu, case 89, Paris, 75005, France
AU: Elias, A
EM: elias@ipgp.jussieu.fr
AF: IPGP - Tectonique, 4 place Jussieu, case 89, Paris, 75005, France
AU: Elias, A
EM: elias@ipgp.jussieu.fr
AF: National Center for Geophysical Research, 59, Rue Zahia Selman, P.O. Box 11-8281, Riad EL-Solh, Beirut, 1107 2260, Lebanon
AU: Singh, S
EM: singh@ipgp.jussieu.fr
AF: IPGP - Tectonique, 4 place Jussieu, case 89, Paris, 75005, France
AU: King, G
EM: king@ipgp.jussieu.fr
AF: IPGP - Tectonique, 4 place Jussieu, case 89, Paris, 75005, France
AU: Briais, A
EM: Anne.Briais@dtp.obs-mip.fr
AF: c- Laboratoire de Dynamique Terrestre et Planetaire - CNRS UMR 5562, Obs. Midi- Pyrenees - 14, Ave. Edouard Belin, Toulouse, 31400, France
AU: Daeron, M
EM: daeron@gps.caltech.edu
AF: California Institute of Technology, Tectonics Observatory, 1200 East California Boulevard, Pasadena, CA 91125, United States
AU: Carton, H
EM: carton@ipgp.jussieu.fr
AF: IPGP - Tectonique, 4 place Jussieu, case 89, Paris, 75005, France
AU: Sursock, A
EM: asursock@cnrs.edu.lb
AF: National Center for Geophysical Research, 59, Rue Zahia Selman, P.O. Box 11-8281, Riad EL-Solh, Beirut, 1107 2260, Lebanon
AU: Jacques, E
EM: jacques@ipgp.jussieu.fr
AF: IPGP - Tectonique, 4 place Jussieu, case 89, Paris, 75005, France
AU: Jomaa, R
EM: rjomaa@cnrs.edu.lb
AF: National Center for Geophysical Research, 59, Rue Zahia Selman, P.O. Box 11-8281, Riad EL-Solh, Beirut, 1107 2260, Lebanon
AU: Klinger, Y
EM: klinger@ipgp.jussieu.fr
AF: IPGP - Tectonique, 4 place Jussieu, case 89, Paris, 75005, France
AB: On July 9, AD 551, a large earthquake, followed by a tsunami destroyed most of the coastal cities of Phoenicia (modern-day Lebanon). This was arguably one of the most devastating historical submarine earthquakes in the eastern Mediterranean. Geophysical data from the Shalimar survey unveils the source of this Mw=7.5 event: rupture of the offshore, hitherto unknown, 100?150 km-long, active, east-dipping Mount Lebanon Thrust (MLT). Deep-towed sonar swaths along the base of prominent bathymetric escarpments reveal fresh, west facing seismic scarps that cut the sediment-smoothed seafloor. The MLT trace comes closest (~ 8 km) to the coast between Beirut and Enfeh, where as 13 radiocarbon-calibrated ages indicate, a shoreline-fringing Vermetid bench suddenly emerged by ~ 80 cm in the 6th century AD. At Tabarja, the regular vertical separation (~ 1 m) of higher fossil benches, suggests uplift by 3 more comparable-size earthquakes since the Holocene sea-level reached a maximum ca. 7-6 ka, implying a 1500?1750 yr recurrence time. Unabated thrusting on the MLT likely orchestrated the growth of Mt. Lebanon since the late Miocene. The newly discovered MLT has been the missing piece in the Dead Sea Transform and eastern Mediterranean tectonic scheme. Identifying the source of the AD 551 event thus ends a complete reassessment of the sources of the major historical earthquakes on the various faults of the Lebanese Restraining Bend of the Levant Fault System (or Dead Sea Transform).
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 8036 Paleoseismology (7221)
DE: 8104 Continental margins: convergent
DE: 8111 Continental tectonics: strike-slip and transform
DE: 8123 Dynamics: seismotectonics
SC: Tectonophysics [T]
MN: 2007 Fall Meeting