Seismic prompt gravity strain signals in a layered spherical Earth  

作　　者：Shenjian Zhang Rongjiang Wang Xiaofei Chen 

机构地区：[1]Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen 518055,China [2]Helmholtz Center Potsdam,GFZ German Research Center for Geosciences,D-14473 Potsdam,Germany [3]Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology,Southern University of Science and Technology,Shenzhen 518055,China [4]Shenzhen Key Laboratory of Deep Offshore Oil and Gas Exploration Technology,Southern University of Science and Technology,Shenzhen 518055,China

出　　处：《Earthquake Science》2023年第5期341-355,共15页地震学报（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Nos.U1901602 and 42204060);Guangdong Provincial Key Laboratory of Geophysical High-Resolution Imaging Technology(No.2022B1212010002);Shenzhen Key Laboratory of Deep Offshore Oil and Gas Exploration Technology(No.ZDSYS20190902093007855);。

摘　　要：Seismic waves generated by an earthquake can produce dynamic perturbations in the Earth’s gravity field before the direct arrival of P-waves.Observations of these so-called prompt elasto-gravity signals by ground-based gravimeters and broadband seismometers have been reported for some large events,such as the 2011 M_(W)9.1 Tohoku earthquake.Recent studies have introduced prompt gravity strain signals(PGSSs)as a new type of observable seismic gravity perturbation that can be used to measure the spatial gradient of the perturbed gravity field.Theoretically,these types of signals can be recorded by indevelopment instruments termed gravity strainmeters,although no successful detection has been reported as yet.Herein,we propose an efficient approach for PGSSs based on a multilayered spherical Earth model.We compared the simulated waveforms with analytical solutions obtained from a homogeneous half-space model,which has been used in earlier studies.This comparison indicates that the effect of the Earth’s structural stratification is significant.With the help of the new simulation approach,we also demonstrated how the PGSSs depend on the magnitude of the seismic source.We further conducted synthetic tests estimating earthquake magnitude using gravity strain signals to demonstrate the potential application of this type of signal in earthquake early warning systems.These results provide essential information for future studies on the synthesis and application of earthquake-induced gravity strain signals.

关 键 词：gravity strain synthetic seismogram earthquake early warning system 

分 类 号：P315.63[天文地球—地震学]