Journal of Tropical Oceanography ›› 2017, Vol. 36 ›› Issue (5): 93-100.doi: 10.11978/2016107CSTR: 32234.14.2016107

• Orginal Article • Previous Articles    

The importance of seafloor topographic correction in identifying and picking seismic phases of OBS

Jian WANG1,2(), Minghui ZHAO1(), Jiazheng ZHANG1, Enyuan HE1,2, Xuelin QIU1   

  1. 1. CAS Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Guangzhou 510301, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2016-10-27 Revised:2016-11-28 Online:2017-09-20 Published:2017-09-22
  • About author:

    Author:QIU Chunhua.E-mail: qiuchh3@mail. sysu.edu.cn

  • Supported by:
    Major Program of National Natural Science Foundation of China (91428204, 91028002);Natural Science Foundation of China ( 41404050, 41176053, 41606064)

Abstract:

Ocean bottom seismometer (OBS) survey is a preferred way to detect deep crustal structures beneath seafloor. It is important to identify and pick reflected/refracted seismic phases correctly in OBS seismic record sections to obtain deep seismic structures. When OBS instruments are deployed on rugged seafloor, the propagating characteristics of seismic phases from the deep lithosphere, such as Pg, PmP and Pn, can be affected by undulated topography. For example, along the seismic line A4M4 cutting across the Zhenbei and Huangyan seamounts in the East Sub-basin of the South China Sea, and along the line Y3Y4 crossing the mid-ocean ridge in the Southwest India Ridge, the highly-varied reliefs increase the difficulty to identify seismic phases in the OBS record sections. Topographic correction is done to eliminate the effects of seafloor topography before picking the travel times of seismic phases. Seismic phases can be identified accurately after the correction according to different apparent velocities and propagating patterns of seismic phases. The method of seafloor topographic correction contributes greatly to recognizing seismic phases and studying crustal structures in these rough terrains, and it can provide references and experiences for the identification of OBS seismic phases in other areas with complex topography.

Key words: ocean bottom seismometer (OBS), seafloor topography, identification of seismic phases, seismic record section