利用人工爆破检验四川芦山及邻区地震定位精度
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摘要
采用MSDP地震分析软件提供的Loc3D和HYPOSAT两种定位方法对芦山科考的8次人工爆破事件进行绝对定位,将定位结果与已知爆破参数进行对比分析。结果显示:两种方法和两种速度模型都能较为准确地测定爆破事件的震中位置,震中定位精度均可优于2.5 km;根据爆破点位置、炸药当量估算震级和定位震级的对比,可验证四川盆地属于介质低衰减区,川西高原属于介质高衰减区,两个区域地震震级平均偏差为0.3;震源深度误差受最近台站震中距的影响比较大,当最近台站震中距小于10 km时,两种定位方法反演的震源深度误差均可优于3 km。
Two positioning methods of MSDP(a seismic analysis software) by Loc3 D and HYPOSAT are used for forth research of 8 times blasting for absolute positioning.The positioning results are compared with the known blasting parameters.The analysis results shows that the two methods and two kinds of velocity model can more accurately determine the position at the epicenter of the blasting events. The epicenter location accuracy can be better than 2.5 km; The comparison between the the location magnitude and the estimated magnitude based on the shot point and the explosive equivalent can verify that the sichuan basin belongs to the low attenuation area of medium and the western sichuan plateau belongs to the high attenuation area of medium. The average deviation of the earthquake magnitude in the two regions is about 0.3. The focal depth error is greatly affected by the epicenter distance of the nearest seismic station. When the epicenter distance of the nearest station is less than 10 km, the focal depth error inversion by the two positioning methods is better than 3 km.
Two positioning methods of MSDP(a seismic analysis software) by Loc3 D and HYPOSAT are used for forth research of 8 times blasting for absolute positioning.The positioning results are compared with the known blasting parameters.The analysis results shows that the two methods and two kinds of velocity model can more accurately determine the position at the epicenter of the blasting events. The epicenter location accuracy can be better than 2.5 km; The comparison between the the location magnitude and the estimated magnitude based on the shot point and the explosive equivalent can verify that the sichuan basin belongs to the low attenuation area of medium and the western sichuan plateau belongs to the high attenuation area of medium. The average deviation of the earthquake magnitude in the two regions is about 0.3. The focal depth error is greatly affected by the epicenter distance of the nearest seismic station. When the epicenter distance of the nearest station is less than 10 km, the focal depth error inversion by the two positioning methods is better than 3 km.
引文
房立华,吴建平,王未来,等.2013.四川芦山MS7.0级地震及其余震序列重定位研究[J].科学通报,58(20):1901-1909.
吴建平,黄媛,张天中,等.2009.汶川MS8.0级地震余震分布及周边区域P波三维速度结构研究[J].地球物理学报,52(2):320-328.
张宇,康健红,张晨侠,等. 2014. 采用LOCSAT和HYPOSAT方法对东北深源地震定位分析[J]. 地震地磁观测与研究,35(3/4):96-99.
Bondár I, McLaughlin K L. 2009. A new ground truth data set for seismic studies [J]. Geophys Res Lett, 80: 465-472.
Bondár I, Myers S C, Engdahl E R, et al. 2004. Epicenter accuracy based on seismic network criteria [J]. Geophys J Int, 156: 483-496.
Chen H,Chiu J M,Pujol J,et al. 2006. A simple algorithm for local earthquake location using 3D VP and VS models: test example in the central United States and in central eastern Taiwan [J]. Bull. Seism. Soc. Am.,96(1):288-305.
Myer S C, Schultz C A. 2000. Calibration of seismic travel time using events with seismically determined locations and origin times [J].EOS, Trans Am geophys Un, 81: F845.
Wu Y M, Chang C H, Hsiao N C, et al. 2003. Relocation of the 1998 Rueyli, Taiwan, earthquake sequence using three-dimensions velocity structure with stations corrections [J]. Terre. Atmos. Oceanic Sci., 14 (4): 421-430.
吴建平,黄媛,张天中,等.2009.汶川MS8.0级地震余震分布及周边区域P波三维速度结构研究[J].地球物理学报,52(2):320-328.
张宇,康健红,张晨侠,等. 2014. 采用LOCSAT和HYPOSAT方法对东北深源地震定位分析[J]. 地震地磁观测与研究,35(3/4):96-99.
Bondár I, McLaughlin K L. 2009. A new ground truth data set for seismic studies [J]. Geophys Res Lett, 80: 465-472.
Bondár I, Myers S C, Engdahl E R, et al. 2004. Epicenter accuracy based on seismic network criteria [J]. Geophys J Int, 156: 483-496.
Chen H,Chiu J M,Pujol J,et al. 2006. A simple algorithm for local earthquake location using 3D VP and VS models: test example in the central United States and in central eastern Taiwan [J]. Bull. Seism. Soc. Am.,96(1):288-305.
Myer S C, Schultz C A. 2000. Calibration of seismic travel time using events with seismically determined locations and origin times [J].EOS, Trans Am geophys Un, 81: F845.
Wu Y M, Chang C H, Hsiao N C, et al. 2003. Relocation of the 1998 Rueyli, Taiwan, earthquake sequence using three-dimensions velocity structure with stations corrections [J]. Terre. Atmos. Oceanic Sci., 14 (4): 421-430.