Study of Normal Modes of Earth's Free Oscillation Based on Changes of Stratified Structure Parameters

2010 ◽  
Vol 53 (2) ◽  
pp. 240-251 ◽  
Author(s):  
Zhao YANG ◽  
He-Ping SUN ◽  
Xiang-E LEI ◽  
Xiao-Dong CHEN
Keyword(s):  
Free Oscillation ◽  
Normal Modes ◽  
Structure Parameters ◽  
Stratified Structure ◽  
Earth’S Free Oscillation

FrosPy: A Modular Python Toolbox for Normal Mode Seismology

2022 ◽  
Author(s):  
Simon Schneider ◽  
Sujania Talavera-Soza ◽  
Lisanne Jagt ◽  
Arwen Deuss
Keyword(s):  
Normal Mode ◽  
Free Oscillation ◽  
Large Time ◽  
Reference Model ◽  
Normal Modes ◽  
Earth Model ◽  
Splitting Function ◽  
Quality Factor Q ◽  
Earth’S Free Oscillation ◽  
Q Values

Abstract We present free oscillations Python (FrosPy), a modular Python toolbox for normal mode seismology, incorporating several Python core classes that can easily be used and be included in larger Python programs. FrosPy is freely available and open source online. It provides tools to facilitate pre- and postprocessing of seismic normal mode spectra, including editing large time series and plotting spectra in the frequency domain. It also contains a comprehensive database of center frequencies and quality factor (Q) values based on 1D reference model preliminary reference Earth model for all normal modes up to 10 mHz and a collection of published measurements of center frequencies, Q values, and splitting function (or structure) coefficients. FrosPy provides the tools to visualize and convert different formats of splitting function coefficients and plot these as maps. By giving the means of using and comparing normal mode spectra and splitting function measurements, FrosPy also aims to encourage seismologists and geophysicists to learn about normal mode seismology and the study of the Earth’s free oscillation spectra and to incorporate them into their own research or use them for educational purposes.

The Earth’s Free Spherical Oscillations of the Great Japan Earthquake

2012 ◽  
Vol 622-623 ◽  
pp. 1664-1669 ◽  
Author(s):  
Ye Wu ◽  
Yong Ge Wan ◽  
Liang Ding
Keyword(s):  
Free Oscillation ◽  
Low Frequency ◽  
Earth Model ◽  
Frequency Signal ◽  
The Earth ◽  
Oscillation Modes ◽  
Spectral Splitting ◽  
Earth’S Free Oscillations ◽  
Earth’S Free Oscillation ◽  
Digital Seismic Network

An M9.0 earthquake struck Japan on March 11, 2011 and the strong earthquake made continuous oscillation of the Earth. We first studied the Earth’s free oscillations using observations of VHZ channel of China Digital Seismic Network (CDSN). Since the frequency response of seismograph in CDSN suppresses the information of low frequency signal, we do not need to remove the solid tide in our data processing. We extracted 72 clear spherical modes of (0S0,0S2to0S72) of the Earth’s free oscillation and 21 harmonic modes and they are consistent and nearly same with the frequencies of the modes of Preliminary Reference Earth Model (PREM). Spectral splitting phenomenon is observed obviously in0S2,0S3,0S4and1S2free oscillation modes.

scholarly journals Split free oscillation amplitudes for the 1960 Chilean and 1964 Alaskan earthquakes

1977 ◽  
Vol 67 (3) ◽  
pp. 651-660 ◽  
Author(s):  
Robert J. Geller ◽  
Seth Stein
Keyword(s):  
Surface Waves ◽  
Volume Change ◽  
Free Oscillation ◽  
Additional Data ◽  
Normal Modes ◽  
Source Mechanisms ◽  
Split Mode ◽  
Theoretical Results

abstract Splitting of the Earth's normal modes was observed for both the 1960 Chilean and 1964 Alaskan earthquakes. The strong peaks in the observed spectrum of each split multiplet correspond to singlets with much higher amplitudes than the others. Using theoretical results we have derived elsewhere (Stein and Geller, 1977a), we are able to predict this pattern. We show that the source mechanisms inferred for these earthquakes from surface waves are consistent with the observed pattern of relative spectral amplitudes of the split modes. However other mechanisms, such as a slow isotropic volume change, are also consistent with the split-mode amplitudes and are excluded only by additional data.

The Earth’s Free Spherical Oscillations of the Chile Earthquake

2012 ◽  
Vol 622-623 ◽  
pp. 1674-1681
Author(s):  
Ye Wu ◽  
Shu Yang ◽  
Liang Ding
Keyword(s):  
Free Oscillation ◽  
Low Frequency ◽  
Earth Model ◽  
The Earth ◽  
Oscillation Modes ◽  
Chile Earthquake ◽  
Spectral Splitting ◽  
Earth’S Free Oscillations ◽  
Earth’S Free Oscillation ◽  
Digital Seismic Network

An M8.8 earthquake struck Chile on February 27, 2010 and the strong earthquake made continuous oscillation of the Earth. We studied the Earth’s free oscillations using observations of VHZ channel of China Digital Seismic Network (CDSN). Since the frequency response of seismograph in CDSN suppresses the information of low frequency signal, we do not need to remove the solid tide in our data processing. We extracted 76 clear spherical modes of (0S0, 0S2 to 0S76) of the Earth’s free oscillation and 78 harmonic modes and they are consistent and nearly same with the frequencies of the modes of Preliminary Reference Earth Model (PREM). Spectral splitting phenomenon is observed obviously in 0S2, 0S3, 0S4 and 1S2 free oscillation modes.

Technical Essentials of the Earth’s Free Oscillation Mode Computation

2017 ◽  
Vol 38 (6) ◽  
pp. 427-441
Author(s):  
Tae-Woong Chung ◽  
◽  
Jin-Soo Shin ◽  
Sung-Ho Na
Keyword(s):  
Free Oscillation ◽  
Oscillation Mode ◽  
Earth’S Free Oscillation

scholarly journals Gravitational Changes of the Earth's Free Oscillation From Earthquakes: Theory and Feasibility Study Using GRACE Inter‐satellite Tracking

2019 ◽  
Vol 124 (7) ◽  
pp. 7483-7503 ◽  
Author(s):  
Khosro Ghobadi‐Far ◽  
Shin‐Chan Han ◽  
Jeanne Sauber ◽  
Frank Lemoine ◽  
Saniya Behzadpour ◽  
...  
Keyword(s):  
Feasibility Study ◽  
Free Oscillation ◽  
Satellite Tracking ◽  
Earth’S Free Oscillation
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