921 Chichi Earthqauke in Taiwan

Seismicity Information

Chinese (Big5) English Version

Insititute of Earth Sciences, Academia Sinica

 

Epicenters of the Mainshock and the Aftershocks


Temporary Seismic Networks

Broadband Array in Taiwan for Seismology (BATS)

Worldwide Seismic Networks

Temporary Seismic Networks

(Data from Seismology Group)

Map of Temporary Seismic Networks

921chichi_tempnet.jpg (498775 bytes)

                            黑色方形:      臨時地震觀測站
                            深黃色圓圈:    921集集主震(規模=7.3)震央位置
                            其他彩色圓圈: 較大餘震(規模>4.5)之震央位置
                            綠色小點:      台灣中部地區過去二十幾年地震分佈
                            黑白圓球:      主震(規模=7.3)與最大餘震(規模=6.8)之地震斷層面解

 

Acceleration Seismogram of Aftershocks

 

Waveform Spectrum of the Aftershocks

 

Broadband Array in Taiwan for Seismology (BATS)

Map of BATS

921chichi_Broadband.jpg (282376 bytes)

 

Broadband Seismic Waveforms

921集集大地震之寬頻地震波觀測資料,圖中時間為格林威治時間。Provided by Honn Kao

 

Focal Mechanisms from BATS

921chichi_batman.jpg (840877 bytes)

Map showing epicenters of the 921 Taiwan earthquake'smain shock (star) and smaller aftershocks (circles) reported by the Central Weather Bureau, Taiwan. Focal mechanisms of aftershocks (yellow beach balls) are determined from waveform inversion of BATS (Broadband Array in Taiwan for Seismology) data. Focal mechanisms clearly show two patterns: events occurred to the north and south of the main shock area show predominant strike-slip faulting, whereas those in the vicinity of main shock show thrust mechanism similar to that of the main shock. This is consistent with the observation shown in the following figure and can be explained as the manifestation of slips along the three sides of a upthrusting block. (Provided by Honn Kao)

 

Worldwide Seismic Networks

Focal Mechanisms

921chichi_teleseis.jpg (813649 bytes)

Map showing epicenters of the 921 Taiwan earthquake's main shock (star) and significant aftershocks (circles). Focal mechanism of the main shock (red beach ball) was reported by the Earthquake Research Institute (ERI) of the Univ. of Tokyo. Focal mechanisms of three aftershocks (yellow beach balls) are determined from inversion of teleseismic P and SH waveforms recorded by Global Seismic Network (GSN). It is clear that immediately to the east of the main shock, earthquakes show similar thrust faulting mechanism, whereas to the south strike-slip faulting becomes predominant. (Provided by Honn Kao)


Copyright @1999 Institute of Earth Sciences, Academia Sinica