A Study on Multiscale Wavelet Analysis in Recognizing Earthquake-Induced Signals in the Medium-to-Short Wavelength Par
Sang-Hoon Park1, Seok-Woo Hong2
1Sang-Hoon Park, Department of Civil Engineering, Dong-Eui University, Busan, South Korea.
2Seok-Woo Hong, Department of Civil Engineering, Dong-Eui University, Busan, South Korea.
Manuscript received on 01 May 2019 | Revised Manuscript received on 15 May 2019 | Manuscript published on 30 May 2019 | PP: 2359-2368 | Volume-8 Issue-7, May 2019 | Retrieval Number: G6387058719/19©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: Mw 9.0 Tohoku-Oki earthquake occurred in the sedimentary area between the Pacific and North American tectonic plates on March 11, 2011. There is no record of a magnitude 9.0 earthquake along Japan Trench except the Jogan earthquake on July 13, AD 869, which may be the only documented incident of similar magnitude and location to the Tohoku-Oki earthquake. Since large crustal deformations indicate mass redistribution within the solid Earth, an earthquake also affects the gravitational field that has the temporal variations reflecting the mass redistribution inside the solid Earth processes. In general, it is difficult to isolate the earthquake anomalies from other signals in the frequency domain since frequencies change spatially due to the contribution of a certain combination of frequencies and this spatial rise of the frequencies is not reflected in the spherical harmonics. In this study, the researchers use monthly GRACE gravity data and apply the multiscale wavelet analysis, based on the Abel-Poisson scale and its corresponding wavelet functions to monthly GRACE gravity data in order to extract the Tohoku-Oki earthquake-induced signals in the medium-to-short-wavelength part. As a result of this largest earthquake, there was some coseismic mass redistribution producing local geoid changes. In March 2011, the coseismic geoid decrease was detected at the northwestern part of Yamagata Prefecture, which increased consistently until February 2011. With regard to the postseismic geoid recovery, changes at the eastern part of northern Honshu near the Miyagi segment and the southern part of the Sanriku segment near the Japan Trench were predominant in August 2011. It is concluded that the geological relationship among these locations played a very important role in the Tohoku-Oki earthquake occurrence. Furthermore, the tectonic plate motion around the Japanese islands may reach a period of geological stability after August 2011.
Keyword: Abel-Poisson Wavelet Function, GRACE Observation, Multiscale Wavelet Analysis, Seismic Geoid Variation Tohoku-Oki Earthquake.
Scope of the Article: Structural Reliability Analysis