A strong earthquake swarm including 7 earthquakes with M≥6.0 occurred in Jiashi, Xinjiang region from January to April, 1997, which is rare for intraplate seismicity. They occurred in Tarim Basin which is relatively ...A strong earthquake swarm including 7 earthquakes with M≥6.0 occurred in Jiashi, Xinjiang region from January to April, 1997, which is rare for intraplate seismicity. They occurred in Tarim Basin which is relatively stable, has no discovered surface rupture and where the deep-seated tectonics are not clear. The Seismological Bureau of Xinjiang Region has made three successful impending predictions for the strong aftershocks and succeeding earthquakes in Jiashi. The injuries and deaths of people have been greatly reduced because of effective measures taken by the local government, and the social and economic results are remarkable. The article introduces a summary of the strong earthquake swarm and the main processes of the prediction, sums up the scientific bases of an impending prediction, and shows that the occurrence of the Jiashi strong earthquake swarm revealed some important scientific problems which should be studied further. The practice of the Jiashi earthquake prediction indicates again展开更多
The borehole strain meter at Wushi station recorded obvious anomaly before Jiashi MS= 6.8 earthquake occurred on February 24, 2003. Its features are as follows. j Anomaly types are complete. The trend anomaly, short-...The borehole strain meter at Wushi station recorded obvious anomaly before Jiashi MS= 6.8 earthquake occurred on February 24, 2003. Its features are as follows. j Anomaly types are complete. The trend anomaly, short-term anomaly, short-imminent anomaly and exponential anomaly appeared 19 months, 56 days, 4 days, and more than 1 month before the event, respectively; k Anomaly is large in magnitude. The maximal magnitude of strain anomaly is 1.7×10?5, which is rare in the past 20-year observation records at Wushi station; l Strain rate fluctuates sharply with obvious alternation of tension and compression. According to the magnitude of strain anomaly, time of expo- nential anomaly appearance and regional features of recorded anomaly, we could predict the magnitude, occur- rence time and potential region to a certain degree.展开更多
We deployed four geo-electric monitoring stations in Sichuan and Yunnan provinces from 2004, using the new generation of equipment (PS-100) and technologies to capture the HRT wave earthquake precursor. Before the Wen...We deployed four geo-electric monitoring stations in Sichuan and Yunnan provinces from 2004, using the new generation of equipment (PS-100) and technologies to capture the HRT wave earthquake precursor. Before the Wenchuan Ms8.0 earthquake, we recorded the HRT wave precursor at the only operating station in Hongge (HG, Δ=465 km) and found that significant impending signal had been recorded at the station in the early morning ( 0―5 am) of 12th of May, 2008. The precursor for this earthquake is consistent with precursors recorded for other strong earthquakes. The measured physical properties (geo-resistivity and telluric-current) show tidal wave period oscillations from several days to several months before the earthquakes and the amplitude of such HT oscillation increases significantly towards the occurrence of an earthquake. These HT and RT waves from the epicenter have a causal relationship with the earthquakes that happened several days later. The arrival time of two RT waves is proportional to the distance from the station to the epicenter. The estimated natural decay of the amplitude is correlated with the natural period (T0) of the earthquake fault, which is proportional to the fault length. From this relationship, we can predict the earthquake magnitude. For magnitude 6―9 earthquakes, the natural period is about 1―6 hours. Such oscillation comes from the epicenter area and they can propagate several thousand kilometers in the Earth's crust. Before a strong earthquake in the shallow crust, the conductive pore fluid will experience major changes before the fault rapture. Such fluid change will emit an oscillation in the pore fluid pressure. This is the mechanism for the HRT wave generation. Since the China Earthquake Administration funded the HRT wave short-term earth-quake prediction project in 2003, the first record of HRT precursor wave has been recorded from the 2004-12-26 Sumatra Mw9.0 earthquake with the largest epicentre distance Δ=2900 km. Thereafter, we have captured HRT waves from more than twenty strong earthquakes, which are well-matched and show repeatability, consistency and regularity. All our observation with the HRT waves demonstrate that HRT wave precursors to earthquakes indeed exist. Strong earthquakes can be predicted and short-term and impending earthquake prediction is achievable in the very near future. From all the observations, including the ones at HG station from Wenchuan Ms8.0 earthquake, we conclude that using HRT wave to predict earthquakes is feasible.展开更多
Based on an interpretation and study of the satellite remote-sensing images of FY-2C thermal infrared 1st wave band （10.3-11.3 μm） designed in China, the authors found that there existed obvious and isolated satell...Based on an interpretation and study of the satellite remote-sensing images of FY-2C thermal infrared 1st wave band （10.3-11.3 μm） designed in China, the authors found that there existed obvious and isolated satellite thermal infrared anomalies before the 5.12 Wenchuan Ms 8.0 Earthquake. These anomalies had the following characteristics： （1） The precursor appeared rather early： on March 18, 2008, i.e., 55 days before the earthquake, thermal infrared anomalies began to occur; （2） The anomalies experienced quite many and complex evolutionary stages： the satellite thermal infrared anomalies might be divided into five stages, whose manifestations were somewhat different from each other. The existence of so many anomaly stages was probably observed for the first time in numerous cases of satellite thermal infrared research on earthquakes; （3） Each stage lasted quite a long time, with the longest one spanning 13 days; （4） An evident geothermal anomaly gradient was distributed along the Longmen seismic fracture zone, and such a phenomenon might also be discovered for the first time in satellite thermal infrared earthquake research. This discovery is therefore of great guiding and instructive significance in the study of the earthquake occurrence itself and the trend of the postearthquake phenomena.展开更多
Three methods of extracting the information of anomalies of a precursory group are put forward, i.e., the mathematical analyses of the synthetic information of earthquake precursors (S), the inhomogeneous degree of pr...Three methods of extracting the information of anomalies of a precursory group are put forward, i.e., the mathematical analyses of the synthetic information of earthquake precursors (S), the inhomogeneous degree of precursory groups (ID) and the values of short-term and impending anomaly in near-source area (NS). Using these methods, we calculate the observational data of deformation, underground fluid and hydrochemical constituents obtained from different seismic stations in the Sichuan-Yunnan region and conclude that the synthetic precursory anomalies of a single strong earthquake with M S6.0 differ greatly from those of the grouped strong earthquakes, for the anomalous information of precursory groups are more abundant. The three methods of extracting the synthetic precursory anomaly and the related numerical results can be applied into the practice of prediction to the grouped strong earthquakes in the Sichuan-Yunnan region. Inhomogeneous degree (ID) of synthetic precursory anomaly can be identified automatically because it takes the threshold of distributive characteristics of the anomalies of precursory group as its criterion for anomaly.展开更多
This paper presents a comprehensive area expansion prediction index method to apply GNSS for short-impending prediction of earthquakes. Based on continuous GNSS observation data from Yunnan Province, a displacement fi...This paper presents a comprehensive area expansion prediction index method to apply GNSS for short-impending prediction of earthquakes. Based on continuous GNSS observation data from Yunnan Province, a displacement field was detected after data cycle-slip repair using precision data processing software and geophysical field effect model correction. The Yunnan area was divided into 56 grid cells for displacement field interpolation to obtain a more uniform displacement field and a strain field variation time series. The pre-earthquake response of each grid-cell expansion time series was evaluated and synthesized to extract a short-impending earthquake anomaly identification index. The results show that this index indicated occurrence times and hypocenter for earthquakes of magnitude M≥5. Fourteen earthquakes were predicted accurately, and there were five false reports. This index can therefore be used for the short-impending prediction of earthquakes.展开更多
地震是极具破坏性与不确定性的自然现象,在人们毫无察觉的情况下地震发生在人口稠密区时,将严重危害人们生命财产安全。人们不断努力了解地震的物理特征和物理危害与环境之间的相互作用,以便在地震发生前发出适当的警报。可靠的地震预...地震是极具破坏性与不确定性的自然现象,在人们毫无察觉的情况下地震发生在人口稠密区时,将严重危害人们生命财产安全。人们不断努力了解地震的物理特征和物理危害与环境之间的相互作用,以便在地震发生前发出适当的警报。可靠的地震预测应包含对地震信号的分析,但是这些信号在地震发生前不明显;因此使用数据驱动机器学习的方法来分析这些信号与地震的联系并预测地震。通过建立观测台网连续监测与地震发生相关的各种物理量或化学量,据此获取的地震前兆信息是地震预测的研究基础。地震发生前,地球物理场发生显著变化,伴随电磁和地声等多种前兆信号,其中电磁和地声信号具有临震特性,是开展地震临震观测预测研究的重要数据来源;因此对地下的电磁扰动和地声信号进行实时监测,获取长期观测数据用于数据驱动机器学习方法预测地震。该文基于AETA数据的临震模型预报,针对多分量地震监测预测系统(Acoustic and Electromagnetic Testing All in one system,AETA)在川滇地区记录的电磁和地声数据,提取时域和频域特征,采用基于随机森林算法、轻量级梯度提升决策树和极度随机树的集成学习方法共同预测该区域的发震情况,选取发震概率最大的子区域中心位置作为震中预测结果,进一步训练LightGBM回归模型以预测此子区域的震级,按周对地震三要素进行预测。实验结果表明,该方法在川滇地区地震风险预测上,准确率可达0.64,震级预测的平均误差为0.38,最小误差为0.00,具有良好的预测效果。展开更多
文摘A strong earthquake swarm including 7 earthquakes with M≥6.0 occurred in Jiashi, Xinjiang region from January to April, 1997, which is rare for intraplate seismicity. They occurred in Tarim Basin which is relatively stable, has no discovered surface rupture and where the deep-seated tectonics are not clear. The Seismological Bureau of Xinjiang Region has made three successful impending predictions for the strong aftershocks and succeeding earthquakes in Jiashi. The injuries and deaths of people have been greatly reduced because of effective measures taken by the local government, and the social and economic results are remarkable. The article introduces a summary of the strong earthquake swarm and the main processes of the prediction, sums up the scientific bases of an impending prediction, and shows that the occurrence of the Jiashi strong earthquake swarm revealed some important scientific problems which should be studied further. The practice of the Jiashi earthquake prediction indicates again
文摘The borehole strain meter at Wushi station recorded obvious anomaly before Jiashi MS= 6.8 earthquake occurred on February 24, 2003. Its features are as follows. j Anomaly types are complete. The trend anomaly, short-term anomaly, short-imminent anomaly and exponential anomaly appeared 19 months, 56 days, 4 days, and more than 1 month before the event, respectively; k Anomaly is large in magnitude. The maximal magnitude of strain anomaly is 1.7×10?5, which is rare in the past 20-year observation records at Wushi station; l Strain rate fluctuates sharply with obvious alternation of tension and compression. According to the magnitude of strain anomaly, time of expo- nential anomaly appearance and regional features of recorded anomaly, we could predict the magnitude, occur- rence time and potential region to a certain degree.
文摘We deployed four geo-electric monitoring stations in Sichuan and Yunnan provinces from 2004, using the new generation of equipment (PS-100) and technologies to capture the HRT wave earthquake precursor. Before the Wenchuan Ms8.0 earthquake, we recorded the HRT wave precursor at the only operating station in Hongge (HG, Δ=465 km) and found that significant impending signal had been recorded at the station in the early morning ( 0―5 am) of 12th of May, 2008. The precursor for this earthquake is consistent with precursors recorded for other strong earthquakes. The measured physical properties (geo-resistivity and telluric-current) show tidal wave period oscillations from several days to several months before the earthquakes and the amplitude of such HT oscillation increases significantly towards the occurrence of an earthquake. These HT and RT waves from the epicenter have a causal relationship with the earthquakes that happened several days later. The arrival time of two RT waves is proportional to the distance from the station to the epicenter. The estimated natural decay of the amplitude is correlated with the natural period (T0) of the earthquake fault, which is proportional to the fault length. From this relationship, we can predict the earthquake magnitude. For magnitude 6―9 earthquakes, the natural period is about 1―6 hours. Such oscillation comes from the epicenter area and they can propagate several thousand kilometers in the Earth's crust. Before a strong earthquake in the shallow crust, the conductive pore fluid will experience major changes before the fault rapture. Such fluid change will emit an oscillation in the pore fluid pressure. This is the mechanism for the HRT wave generation. Since the China Earthquake Administration funded the HRT wave short-term earth-quake prediction project in 2003, the first record of HRT precursor wave has been recorded from the 2004-12-26 Sumatra Mw9.0 earthquake with the largest epicentre distance Δ=2900 km. Thereafter, we have captured HRT waves from more than twenty strong earthquakes, which are well-matched and show repeatability, consistency and regularity. All our observation with the HRT waves demonstrate that HRT wave precursors to earthquakes indeed exist. Strong earthquakes can be predicted and short-term and impending earthquake prediction is achievable in the very near future. From all the observations, including the ones at HG station from Wenchuan Ms8.0 earthquake, we conclude that using HRT wave to predict earthquakes is feasible.
基金support from the Key Project of Hainan Province Scientific and Technical Plan(grant No.06701)
文摘Based on an interpretation and study of the satellite remote-sensing images of FY-2C thermal infrared 1st wave band （10.3-11.3 μm） designed in China, the authors found that there existed obvious and isolated satellite thermal infrared anomalies before the 5.12 Wenchuan Ms 8.0 Earthquake. These anomalies had the following characteristics： （1） The precursor appeared rather early： on March 18, 2008, i.e., 55 days before the earthquake, thermal infrared anomalies began to occur; （2） The anomalies experienced quite many and complex evolutionary stages： the satellite thermal infrared anomalies might be divided into five stages, whose manifestations were somewhat different from each other. The existence of so many anomaly stages was probably observed for the first time in numerous cases of satellite thermal infrared research on earthquakes; （3） Each stage lasted quite a long time, with the longest one spanning 13 days; （4） An evident geothermal anomaly gradient was distributed along the Longmen seismic fracture zone, and such a phenomenon might also be discovered for the first time in satellite thermal infrared earthquake research. This discovery is therefore of great guiding and instructive significance in the study of the earthquake occurrence itself and the trend of the postearthquake phenomena.
文摘Three methods of extracting the information of anomalies of a precursory group are put forward, i.e., the mathematical analyses of the synthetic information of earthquake precursors (S), the inhomogeneous degree of precursory groups (ID) and the values of short-term and impending anomaly in near-source area (NS). Using these methods, we calculate the observational data of deformation, underground fluid and hydrochemical constituents obtained from different seismic stations in the Sichuan-Yunnan region and conclude that the synthetic precursory anomalies of a single strong earthquake with M S6.0 differ greatly from those of the grouped strong earthquakes, for the anomalous information of precursory groups are more abundant. The three methods of extracting the synthetic precursory anomaly and the related numerical results can be applied into the practice of prediction to the grouped strong earthquakes in the Sichuan-Yunnan region. Inhomogeneous degree (ID) of synthetic precursory anomaly can be identified automatically because it takes the threshold of distributive characteristics of the anomalies of precursory group as its criterion for anomaly.
基金supported by the National 973 Project of China (No. 2013CB733303)the National Natural Science Foundation of China (No. 41474093)+4 种基金the Key Natural Science Foundation of Hubei Province (No. 2014CFA110)the open fund of Key Laboratory of Geospace Environment and Geodesy, Ministry of Education (No. 15-02-07)the China Earthquake Administration’s Earthquake Science and Technology Spark Program (No. XH15037SX)Special fund of earthquake science and technology of Yunnan Earthquake Agency (No. 2017ZX02)the Jiancheng Li Academician Workstation (No. 2015IC015)
文摘This paper presents a comprehensive area expansion prediction index method to apply GNSS for short-impending prediction of earthquakes. Based on continuous GNSS observation data from Yunnan Province, a displacement field was detected after data cycle-slip repair using precision data processing software and geophysical field effect model correction. The Yunnan area was divided into 56 grid cells for displacement field interpolation to obtain a more uniform displacement field and a strain field variation time series. The pre-earthquake response of each grid-cell expansion time series was evaluated and synthesized to extract a short-impending earthquake anomaly identification index. The results show that this index indicated occurrence times and hypocenter for earthquakes of magnitude M≥5. Fourteen earthquakes were predicted accurately, and there were five false reports. This index can therefore be used for the short-impending prediction of earthquakes.
文摘地震是极具破坏性与不确定性的自然现象,在人们毫无察觉的情况下地震发生在人口稠密区时,将严重危害人们生命财产安全。人们不断努力了解地震的物理特征和物理危害与环境之间的相互作用,以便在地震发生前发出适当的警报。可靠的地震预测应包含对地震信号的分析,但是这些信号在地震发生前不明显;因此使用数据驱动机器学习的方法来分析这些信号与地震的联系并预测地震。通过建立观测台网连续监测与地震发生相关的各种物理量或化学量,据此获取的地震前兆信息是地震预测的研究基础。地震发生前,地球物理场发生显著变化,伴随电磁和地声等多种前兆信号,其中电磁和地声信号具有临震特性,是开展地震临震观测预测研究的重要数据来源;因此对地下的电磁扰动和地声信号进行实时监测,获取长期观测数据用于数据驱动机器学习方法预测地震。该文基于AETA数据的临震模型预报,针对多分量地震监测预测系统(Acoustic and Electromagnetic Testing All in one system,AETA)在川滇地区记录的电磁和地声数据,提取时域和频域特征,采用基于随机森林算法、轻量级梯度提升决策树和极度随机树的集成学习方法共同预测该区域的发震情况,选取发震概率最大的子区域中心位置作为震中预测结果,进一步训练LightGBM回归模型以预测此子区域的震级,按周对地震三要素进行预测。实验结果表明,该方法在川滇地区地震风险预测上,准确率可达0.64,震级预测的平均误差为0.38,最小误差为0.00,具有良好的预测效果。
