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Ionospheric response following the M w 7.8 Gorkha earthquake on 25 April 2015
Author(s) -
Liu Haitao,
Ding Feng,
Zhao Biqiang,
Li Jianyong,
Hu Lianhuan,
Wan Weixing,
Ning Baiqi
Publication year - 2017
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja023079
Subject(s) - epicenter , total electron content , tec , seismology , ionosphere , geology , rayleigh wave , seismogram , amplitude , geodesy , quake (natural phenomenon) , microseism , geophysics , surface wave , physics , optics
A detailed observation of the coseismic ionospheric disturbances (CIDs) after the M w 7.8 Gorkha earthquake has been carried out using total electron content (TEC) data from 333 GPS stations. This inland earthquake occurred on 25 April 2015, at a depth of ~15 km. Following the quake at 6:11 UT, groups of CIDs were observed from 06:18 to 07:00 UT. The CIDs we observed could be classified into three groups: CIDs related to gravity waves (GWs), CIDs related to acoustic waves (AWs), and CIDs related to seismic Rayleigh surface waves. The GW‐related CIDs traveled at a velocity of ~500 m/s. They were mainly observed to the south and north of the epicenter, within 600 km of the event, with a maximum amplitude of 0.18 total electron content unit (TECU; 1 TECU = 10 16 el m −2 ). The AW‐related CIDs traveled at a velocity of ~700–1400 m/s. They could be observed for 1000 km in all directions from the epicenter, with an amplitude of ~0.3 TECU. The CIDs related to Rayleigh waves could be observed only to the east of the epicenter, at a maximum distance of 1800 km. They had an apparent velocity of ~2.0–2.3 km/s. Through comparing the seismogram data from Incorporated Research Institutions for Seismology to the TEC data, we found that the azimuthal characteristics of the ground vibrations agree with the directivity of the CIDs related to Rayleigh surface waves.