An earthquake with M_S4. 6 occurred at 17: 08 p. m.,May 22,2016 in Chaoyang County,Liaoning Province. We used the P-wave first motion method,TDMT method,and CAP method to determine the focal mechanisms and the PTD met...An earthquake with M_S4. 6 occurred at 17: 08 p. m.,May 22,2016 in Chaoyang County,Liaoning Province. We used the P-wave first motion method,TDMT method,and CAP method to determine the focal mechanisms and the PTD method and sP n-Pn method to determine the focal depth. The focal mechanism results of the three methods are consistent. The depth results of the CAP method,PTD method and sP n-Pn method are close. We used the double difference location method to relocate earthquakes in 2009-2016,and obtained the strikes and dip angles of the small earthquake distributions with the help of simulated annealing algorithm and gauss Newton algorithm fitting. According to the focal mechanism results,the depth results,the characteristics of small earthquake distributions and the structural characteristics of the source area,the seismogenic fault strike is NEE and the main pressure force direction is NNW. The earthquake focal mechanism is for a normal fault type with a little left-lateral strike slip motion.展开更多
On July 20,2012,the Ms 4.9 Baoying Earthquake occurred near the junction of Baoying County and Gaoyou City in Jiangsu Province,eastern China.Due to no obvious surface rupture and limited observation of earthquake sequ...On July 20,2012,the Ms 4.9 Baoying Earthquake occurred near the junction of Baoying County and Gaoyou City in Jiangsu Province,eastern China.Due to no obvious surface rupture and limited observation of earthquake sequence,the seismogenic structure of the Ms 4.9 Baoying Earthquake is still unclear.In this study,80 earthquakes provided by China Earthquake Network Center(CENC)are first relocated;and then the relocated 75 events with high signal-to-noise ratios as templates are utilized to scan through continuous waveform data(July 11 to August 31,2012)using graphics processing unit-based match and locate(GPU-M&L)technique.Then the Deep Denoiser,a deeplearning-based noise reduction technique,is used to further confirm some newly detected events;and the double-difference relocation(Hypo DD)algorithm is used to relocate the earthquakes.We detect and relocate more than twice as many events as the CENC routine catalog,which includes 15 foreshocks and 230 aftershocks.The results show that the foreshocks are mainly distributed in the NW direction along the extended SE section of the blind Xiagonghe fault(XF),which is orthogonal to the strike of the seismogenic fault of the Ms 4.9 Baoying Earthquake(Yangchacang-Sangshutou fault,named YSF).Most of the aftershocks are generally distributed along the NNE-trending YSF and illuminate a steeply dipping plane.This study reveals detailed spatiotemporal evolution of the earthquake sequence and suggests that the buried XF extends southeastward and cuts through the NNE-trending seismogenic YSF.展开更多
基金jointly sponsored by the Special Program of Youth Training for the National Seismological Network of CEA(20160506)the Earthquake Science and Technology Spark Plan of CEA(XH14012Y)
文摘An earthquake with M_S4. 6 occurred at 17: 08 p. m.,May 22,2016 in Chaoyang County,Liaoning Province. We used the P-wave first motion method,TDMT method,and CAP method to determine the focal mechanisms and the PTD method and sP n-Pn method to determine the focal depth. The focal mechanism results of the three methods are consistent. The depth results of the CAP method,PTD method and sP n-Pn method are close. We used the double difference location method to relocate earthquakes in 2009-2016,and obtained the strikes and dip angles of the small earthquake distributions with the help of simulated annealing algorithm and gauss Newton algorithm fitting. According to the focal mechanism results,the depth results,the characteristics of small earthquake distributions and the structural characteristics of the source area,the seismogenic fault strike is NEE and the main pressure force direction is NNW. The earthquake focal mechanism is for a normal fault type with a little left-lateral strike slip motion.
基金supported by the National Natural Science Foundation of China(No.U1939203)the National Key R&D Program of China(No.2017YFC150040)Shanghai Sheshan National Geophysical Observatory(No.2020K02)。
文摘On July 20,2012,the Ms 4.9 Baoying Earthquake occurred near the junction of Baoying County and Gaoyou City in Jiangsu Province,eastern China.Due to no obvious surface rupture and limited observation of earthquake sequence,the seismogenic structure of the Ms 4.9 Baoying Earthquake is still unclear.In this study,80 earthquakes provided by China Earthquake Network Center(CENC)are first relocated;and then the relocated 75 events with high signal-to-noise ratios as templates are utilized to scan through continuous waveform data(July 11 to August 31,2012)using graphics processing unit-based match and locate(GPU-M&L)technique.Then the Deep Denoiser,a deeplearning-based noise reduction technique,is used to further confirm some newly detected events;and the double-difference relocation(Hypo DD)algorithm is used to relocate the earthquakes.We detect and relocate more than twice as many events as the CENC routine catalog,which includes 15 foreshocks and 230 aftershocks.The results show that the foreshocks are mainly distributed in the NW direction along the extended SE section of the blind Xiagonghe fault(XF),which is orthogonal to the strike of the seismogenic fault of the Ms 4.9 Baoying Earthquake(Yangchacang-Sangshutou fault,named YSF).Most of the aftershocks are generally distributed along the NNE-trending YSF and illuminate a steeply dipping plane.This study reveals detailed spatiotemporal evolution of the earthquake sequence and suggests that the buried XF extends southeastward and cuts through the NNE-trending seismogenic YSF.
