5:15 PM - 6:45 PM
[U15-P41] Comparison of observed PGVs during the 2024 Noto Peninsula earthquake and the 1999 Chichi, Taiwan, earthquake
Keywords:2024 Noto Peninsula Earthquake, 1999 Chichi, Taiwan, earthquake, PGV, attenuation characteristics
On 1st January 2024, an earthquake of Mw 7.5 occurred in Noto peninsula, Ishikawa prefecture, Japan. In this study, we compared the attenuation characteristics of the peak ground velocity (PGV)observed during the Mw 7.5 Noto Peninsula earthquake and the Mw 7.62 Chichi, Taiwan, earthquake.
The strong motion records for Noto Peninsula earthquake are those recorded by K-NET and KiK-net. PGV is derived by integrating the filtered acceleration waveform to velocity waveform. The larger value of two horizontal components is used in the analysis. We used the fault model estimated by GSI to calculate the closest distance from an observation station to the seismic fault (Fault distance). All the data for the Chichi earthquake are adopted from the NGA-W2 flatfiles. Since the value of PGVs in NGA-W2 flatfiles is defined as the mean value of PGVs of two horizontal components, the data of PGVs for Chichi earthquake are multiplied by a factor of 1.1 in this study. All the observed PGVs are divided by an amplification factor defined by Si and Midorikawa (1999) to derive PGV at stiff ground with VS30=600m/s.
Fig.1 shows the attenuation characteristics of PGV for both the 2024 Noto Peninsula earthquake and the 1999 Chichi earthquake. The figure shows that (1) The figure shows that the PGVs observed for both earthquakes overlap at observation stations farther than about 20 km, indicating that the average strength of the ground motions is similar; (2) for the observation stations closer than about 20 km, the observed PGVs for the Noto Peninsula earthquake, which has a slightly smaller Mw, are on average larger than the data for the Chichi earthquake. This is partially because, in the Noto Peninsula Earthquake, the observation records were only obtained at the hanging-wall area closer than approximately 20 km, and there were no observation records on the footwall area, where the ground motion is thought to be weaker on average than the hanging-wall area. On the other hand, for the Chichi earthquake that occurred in inland Taiwan, the observation records were obtained on both the hanging-wall area and the footwall area, and the observed PGVs were distributed above and below the predictions by the ground motion model proposed by Si and Midorikawa (1999).
The strong motion records for Noto Peninsula earthquake are those recorded by K-NET and KiK-net. PGV is derived by integrating the filtered acceleration waveform to velocity waveform. The larger value of two horizontal components is used in the analysis. We used the fault model estimated by GSI to calculate the closest distance from an observation station to the seismic fault (Fault distance). All the data for the Chichi earthquake are adopted from the NGA-W2 flatfiles. Since the value of PGVs in NGA-W2 flatfiles is defined as the mean value of PGVs of two horizontal components, the data of PGVs for Chichi earthquake are multiplied by a factor of 1.1 in this study. All the observed PGVs are divided by an amplification factor defined by Si and Midorikawa (1999) to derive PGV at stiff ground with VS30=600m/s.
Fig.1 shows the attenuation characteristics of PGV for both the 2024 Noto Peninsula earthquake and the 1999 Chichi earthquake. The figure shows that (1) The figure shows that the PGVs observed for both earthquakes overlap at observation stations farther than about 20 km, indicating that the average strength of the ground motions is similar; (2) for the observation stations closer than about 20 km, the observed PGVs for the Noto Peninsula earthquake, which has a slightly smaller Mw, are on average larger than the data for the Chichi earthquake. This is partially because, in the Noto Peninsula Earthquake, the observation records were only obtained at the hanging-wall area closer than approximately 20 km, and there were no observation records on the footwall area, where the ground motion is thought to be weaker on average than the hanging-wall area. On the other hand, for the Chichi earthquake that occurred in inland Taiwan, the observation records were obtained on both the hanging-wall area and the footwall area, and the observed PGVs were distributed above and below the predictions by the ground motion model proposed by Si and Midorikawa (1999).