Abstract：An MW9.0 earthquake occurred near the Pacific coast of Tohoku, Japan on March 11, 2011. Many internationally well-known research institutions and scholars launched different earthquake focal mechanism solutions, with many scholars evaluating these solutions. We simulate the free oscillation signal excited by the Japan earthquake. Comparing 15 seismograph observations of the seismic network in Hubei, we evaluate observations of these seismographs in low frequency band and analyze the observation ability in different frequency bands. The results show that in the 1.5 mHz to 4.5 mHz bands, there is excellent agreement between observations and synthetics; in >4.5 mHz bands, observed amplitude is significantly lower than in synthetics. In addition, we assess the observational conditions of instruments based on the spheroidal modes in the 1.5 mHz to 4.5 mHz band: most of the seismograph observation conditions are good; the conformity to simulation value and the observed value of 10 stations is up to 90%; the conformity of YC, NZH, DJI is poor.
MENG Fangjie,ZHANG Yan. Investigation of Low Frequency Characteristics of the Hubei Earthquake Network Seismograph Using Earth’s Free Oscillation[J]. jgg, 2019, 39(2): 195-198.
