Seismic activity characteristics in the East Sea area
Authors: Hoan Vu Thi , Lu Ngo Thi , V. Rodkin M. , Quang Nguyen , Huong Phan Thien 
Published: June 2018

In this paper, seismic activity characteristics in the East Sea area was analyzed by authors on the base of the unified earthquake catalog (1900-2017), including 131505 events with magnitude 3 ≤ Mw ≤ 8.4. The seismic intensity in the East Sea during the period 1900-2017 is characterized by the earthquake representative level Mw = 4.7. The strong earthquake activity in the East Sea area clearly shows the regularity in each stage. In the period from 1900 to 2017, the East Sea area has four periods of strong earthquake activity, each stage is nearly 30 years with particular characteristics. The distribution of the maximum earthquake quantities by years has a cyclicity in all four periods. In each stage there are 1-2 strong earthquakes with Mmax ≥ 8.0. The strong earthquakes with Mmax ≥ 7.5 have occurred by a repeatable rule of 3-5 years in all four stages. This allows the prediction of the maximum earthquake repeat cycle of Mmax ≥ 7.5 in the study area is 3-5 years. In other hand, the maximum magnitude values for the East Sea region has assessed by GEV method with several different predict periods (20, 40, 60, 80, 100 years), with predicted probability 80%. We concluded that it is possible that earthquake have Mmax = 8.7 will occur in next 100 years.ReferencesBautista C.B., Bautista M.L.P., Oike K., Wu F.T., Punongbayan R.S., 2001. A new insight on the geometry of subducting slabs in northern Luzon, Philippines. Tectonophysics, 339, 279-310.Bui Cong Que, et al., 2010. Seismic and tsunamis hazard in coastal Viet Nam. Natural Science and Technology Publishing House, 311p.Bui Van Duan, Nguyen Cong Thang, Nguyen Van Vuong, Pham Dinh Nguyen, 2013. The magnitude of the largest possible earthquake in the Muong La-Bac Yen fault zone. J. Sci. of the Earth, 35, 53-59 (in Vietnamese).Cao Dinh Trieu, Pham Nam Hung, 2008. Deep-seated fault zone presents the risk of strong earthquakes in the East and South Vietnam Sea. 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