Recently in 2020, in southern Saudi Arabia three felt earthquakes occurred in Asir region, in the Khamis Mushait, Ahad Rafidah, and AL-Shuqiq area, of magnitude 3.45, 3.1, and 3.5, respectively. The most interest ing event was the earthquake that occurred in Khamis Mushait area, along a lake formed behind the Tadhah Dam (~7 km), fearing any damage to the dam’s body and the consequent destruction. Moment tensors for each event were computed for determining fault plane solutions, seismic moment, moment magnitude (Mw) and the CLVD ratio. In addition, the frequency contents in the waveforms of each event were identified. The obtained focal mechanisms represent different styles of faulting, normal movement with strike slip and strike slip with reverse. These tectonic movements on faults parallel to the Red Sea refer to the tensional forces due to the Red Sea rift system. These events occurred due to a natural tectonic movement, with considering the Khamis Mushait event as an induced event because of the lake behind the Dam. Many previous seismic hazard assessment studies have been conducted in southern Saudi Arabia without considering these recent seismic sources. Thus, our study pro vides new information related to detecting of new active seismic sources, which contributes to updating studies of seismic risk assessment in this region. In addition, our study push es us to establish other additional seismic stations around these new seismic sources. This in turn will play a pivotal role in controlling seismic sourc es and then reassessing the seismic hazard in southern Saudi Arabia.
KeywordsNew Seismic SourcesLocal and Regional StressesUpdating Seismic Hazard
Stern, B. and Johnson, P.R. (2010) Continental Lithosphere of the Arabian Plate: A Geologic, Petrologic, and Geophysical Synthesis. Earth-Science Reviews, 101, 29-67. https://doi.org/10.1016/j.earscirev.2010.01.002
Vita-Finzi, C. (2001) Neotectonics at the Arabian Plate Margin. Journal Structural Geology, 23, 521-530. https://doi.org/10.1016/S0191-8141(00)00117-6
Hessam, K., Nilfouroushan, F. and Christopher, T.J. (2006) Active Deformation within the Zagros Mountain Deduced from GPS Measurements. Journal of Geological Society, 163, 143-148. https://doi.org/10.1144/0016-764905-031
Abdel-Gawad, M. (1969) New Evidence of Transcurrent Movements in the Red Sea Area and Petroleum Implications. AAPG Bulletin, 53, 1466-1479. https://doi.org/10.1306/5D25C861-16C1-11D7-8645000102C1865D
Freund, R., Zak, I. and Garfunkel, Z. (1968) Age and Rate of the Sinistral Movement along the Dead Sea Rift. Nature, 220, 253-255. https://doi.org/10.1038/220253a0
El-Isa, Z. and Al Shanti, A. (1989) Seismicity and Techtonics of the Red Sea and Western Arabia. Geophysical Journal International, 97, 449-457. https://doi.org/10.1111/j.1365-246X.1989.tb00515.x
Al-Amri, A.M.S. (1995) Recent Seismicity Activity in the Northern Red Sea. Journal of Geodynamics, 20, 243-253. https://doi.org/10.1016/0264-3707(95)00007-V
Al-Saud, M.M. (2008) Seismic Characteristics and Kinematic Models of Makkah and Central Red Sea Regions. Arabian Journal of Geosciences, 1, 49-61. https://doi.org/10.1007/s12517-008-0004-2
Bosworth, W. (2015) Geological Evolution of the Red Sea: Historical Background, Review, and Synthesis. In: Rasul, N. and Stewart, I., Eds., The Red Sea, Springer Berlin, 45-78. https://doi.org/10.1007/978-3-662-45201-1_3
Youssef, S.E.H. (2015) Seismicity and Seismotectonic Setting of the Red Sea and Adjacent Areas. In: Rasul, N. and Stewart, I., Eds., The Red Sea, Springer, Berlin, 151-159. https://doi.org/10.1007/978-3-662-45201-1_8
Zahran, H.M. and El-Hadidy, S.M. (2017) Seismic Hazard Assessment for Harat Lynayyir—A Lava Field in Western Saudi Arabia. Soil Dynamics and Earthquake Engineering, 100, 428-444. https://doi.org/10.1016/j.soildyn.2017.06.009
Poirier, J.P. and Taher, M.A. (1980) Historical Seismicity in the Near and Middle East, North Africa and Spain from Arabic Documents (VIIth-Xviith Century). Bulletin of the Seismological Society of America, 70, 2185-2201. https://doi.org/10.1785/BSSA0700062185
A.S.S.A. (1983) Dhamar Earthquake of 13/12/82 A Report Submitted to the Yemeni Government. Araibi Text.
Alsinawi, S.A. (1986) Historical Seismicity of the Arab Region. Proceedings of the Third Arab Seismological Seminar, Riyadh Saudi Arabia, 11-33.
Amdraseys, N.N. and Melville, C.P. (1983) Seismicity of Yemen. Nature, 303, 321-323. https://doi.org/10.1038/303321a0
Ambraseys, N.N. and Melville, C.P. (1994) The Seismicity of Egypt, Arabia and the Red Sea—A Historical Review. Cambridge University Press, Cambridge. https://doi.org/10.1017/CBO9780511524912
Vladimir, M. and Dragi, D. (2004) Strong Motion Instrumentation of Dams in Macedonia Some Experience and Results. 13th World Conference on Earthquake Engineering Vancouver, Canada, 1-6August 2004, Paper No. 475.
Udias, A., Vallina, A.U., Madariaga, R. and Buforn, E. (2014) Source Mechanisms of Earthquakes: Theory and Practice. Cambridge University Press, Cambridge. https://doi.org/10.1017/CBO9781139628792
Gilbert, F. (1971) Excitation of the Normal Modes of the Earth by Earthquake Sources. Geophysical Journal International, 22, 223-226. https://doi.org/10.1111/j.1365-246X.1971.tb03593.x
Miller, A., Stewart, R.L., White, R.A., Baptie, B.J., Aspinall, W.P., Latchman, J.L. and Voight, B. (1998) Seismicity Associated with Dome Growth and Collapse at the Soufriere Hills Volcano, Montserrat. Geophysical Research Letters, 25, 3401-3404. https://doi.org/10.1029/98GL01778
Haderbeck, J.L. and Peter, M.S. (2003) Using S/P Amplitude Ratios to Constrain the Focal Mechanisms of Small Earthquakes. Bulletin of Seismological Society of America, 93, 2434-2344. https://doi.org/10.1785/0120020236
Fojt’ıkov’a, L., Vavryˇcuk, V., Cipciar, A. and Madar’as, J. (2010) Focal Mechanisms of Micro-Earthquakes in the Dobrá Voda Seismoactive Area in the Malé Karpaty Mts. (Little Carpathians), Slovakia. Tectonophysics, 492, 213-229. https://doi.org/10.1016/j.tecto.2010.06.007
Godano, M., Bardainne, T., Regnier, M. and Deschamps, A. (2011) Moment-Tensor Determination by Nonlinear Inversion of Amplitudes. Bulletin of the Seismological Society of America, 101, 366-378. https://doi.org/10.1785/0120090380
Dziewonski, A.M., Chou, T.A. and Woodhouse, J.H. (1981) Determination of Earthquake Source Parameters from Waveform Data for Studies of Regional and Global Seismicity. Journal of Geophysical Research: Solid Earth, 86, 2825-2852. https://doi.org/10.1029/JB086iB04p02825
Sipkin, S.A. (1986) Estimation of Earthquake Source Parameters by the Inversion of Waveform Data: Global Seismicity, 1981-1983. Bulletin of the Seismological Society of America, 76, 1515-1541. https://doi.org/10.1785/BSSA0760061515
Eyre, T.S., Bean, C.J., De Barros, L., O’Brien, G.S., Martini, F., Lokmer, I., Mora, M.M., Pacheco, J.F. and Soto, G.J. (2013) Moment Tensor Inversion for the Source Location and Mechanism of Long Period (LP) Seismic Events from 2009 at Turrialba Volcano, Costa Rica. Journal of Volcanology and Geothermal Research, 258, 215-223. https://doi.org/10.1016/j.jvolgeores.2013.04.016
Herrmann, R.B. (2013) Computer Programs in Seismology: An Evolving Tool for Instruction and Research. Seismological Research Letters, 84, 1081-1088. https://doi.org/10.1785/0220110096
Jost, M. and Herramann, R. (1989) A Student’s Guide to and Review of Moment Tensor. Seismological Research Letters, 60, 37-57. https://doi.org/10.1785/gssrl.60.2.37
Herrmann, R. and Wang, C. (1985) A Comparison of Synthetic Seismograms. Bulletin of Seismological Society of America, 75, 41-56.
Talwani, P. (1988) The Intersection Model for Intraplate Earthquakes. Siesmological Research Letters, 59, 305-310. https://doi.org/10.1785/gssrl.59.4.305
Talwani, P. and Rajendran, K. (1991) Some Seismological and Geometric Features of Intraplate Earthquakes. Tectonophysics, 186, 19-41. https://doi.org/10.1016/0040-1951(91)90383-4
Sibson, R. and Lee, G. (1998) Dip Range for Intracontinental Reverse Fault Ruptures: Truth Not Stranger than Friction? Bulletin of the Seismological Society of America, 88, 1014-1022. https://doi.org/10.1785/BSSA0880041014
Vavryčuk, V. (2011) Detection of High-Frequency Tensile Vibrations of a Fault during Shear Rupturing: Observations from the 2008 West Bohemia Swarm. Geophysical Journal International, 186, 1404-1414. https://doi.org/10.1111/j.1365-246X.2011.05122.x
Vavryčuk, V. (2013) Is the Seismic Moment Tensor Ambiguous at a Material Interface? Geophysical Journal International, 194, 395-400. https://doi.org/10.1093/gji/ggt084
Vavryčuk, V. (2015) Moment Tensor Decompositions Revisited. Journal of Seismology, 19, 231-252. https://doi.org/10.1007/s10950-014-9463-y
Power, J.A., Lahr, C.J., Page, R.A., Chouet, B.A., Stephens, C.D., Harlow, D.H., Murray, T.L. and Davies, J.N. (1994) Seismic Evolution of the 1989-1990 Eruption Sequence of Redoubt Volcano, Alaska. Journal of Volcanology and Geothermal Research, 62, 69-94. https://doi.org/10.1016/0377-0273(94)90029-9
Chouet, B. (1988) Resonance of a Fluid-Driven Crack: Radiation Properties and Implications for the Source of Long-Period Events and Harmonic Tremor. Journal of Geophysical Research: Solid Earth, 93, 4375-4400. https://doi.org/10.1029/JB093iB05p04375
Neuberg, J. (2000) Characteristics and Causes of Shallow Seismicity in Andesite Volcanoes. Philosophical Transactions of the Royal Society of London, 358, 1533-1546. https://doi.org/10.1098/rsta.2000.0602
Al-Amri, A.M. (1995) Preliminary Seismic Hazard Assessment of the Southern Red Sea Region. Europian Earthquake Engineering, 33-38.
Al-Amri, A.M. and Al-Khalifah, T. (2004) Improving the Level of Seismic Hazard Parameters in Saudi Arabia Using Earthquake Location and Magnitude Calibration. Project No. 20-68, King Abdul Aziz City for Science and Technology, Riyadh.
Al-Haddad, M., Siddiqi, G.H., Al-Zaid, R., Arafah, A., Necioglu, A. and Turkelli, N. (1994) A Basis for Evaluation of Seismic Hazard and Design for Saudia Arabia. Earthquake Spectra, 10, 231-258. https://doi.org/10.1193/1.1585773
Barazangi, M. (1981) Evaluation of Seismic Risk along the Western Part of the Arabian Plate: Discussion and Recommendations. Bulletin of Faculty of Earth Science, 4, 77-87.
Thenhaus, P.C., Algermissen, S., Perkins, D., Hansen, S. and Diment, W. (1987) Probabilistic Estimates of the Seismic Ground-Motion Hazards in Western Saudi Arabia. U.S. Government Publishing Office, Washington DC. https://doi.org/10.3133/ofr87173