On “410”discontinuity depth of the Tonga-Fiji subduction zone by the sP precursor recorded by Gansu seismic network
Qin Manzhong
Zhang Yuansheng
Liu Xuzhou
Li Shuncheng
Abstract：The sP seismic phase of the Tonga-Fiji subduction zone have a clear image in the Gansu Digital Seismic Network and southeastern Gansu temporary observation array.In this paper,we extracted the weak precursors s410 P by slant stack method,and the s410 P precursors are produced by deep focus earth-quakes that result from near-source underside reflection off “410”.We compute the depth of “410”discontinuity by using the differential travel time between sP and its precursor s410 P near Tonga-Fiji subduction zone based on the modified velocity model (IASP91 Tonga)in this zone based on CRUST1.0 model.The depth of “410”discontinuity is about 398.5 km,and uplifted about 11.5 km, which maybe relate to the interaction of the subduction zone and the “410”dis-continuity in the near-source zone.This result is of great significance to recog-nize the complex structure of subduction zones and objectively understand the dynamic process of the deep Earth.
Keywords：seismic phase sPprecursor s410 Pdiscontinuitysubduction zoneGansu Digital Seismic Networksoutheastern Gansu temporary observation array
Publication Date：2016-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 53-58 )