An important task in seismic hazard assessment is the estimation of intensity and frequency of rare strong seismic shaking, in particular, the long-term peak ground velocity values(PGVs). A recently proposed method is...An important task in seismic hazard assessment is the estimation of intensity and frequency of rare strong seismic shaking, in particular, the long-term peak ground velocity values(PGVs). A recently proposed method is suitable for simply estimating PGVs based on the examination of the magnitude of displacements of rock blocks. The effectiveness of this method is demonstrated by results of studies on the source zones of two large earthquakes and a vicinity of one strong explosion. In this study, the method is applied to the examination of archeoseismological data from the ancient Rehovot-ba-Negev city and other ancient cities from the Negev desert(in Southern Israel) where numerous evidences of presumable seismic damage were found earlier. The cities and also a sophisticated irrigation system within the region, which existed in the Negev desert, were abandoned however in the middle of the seventh century. The abandonment could be caused by a combined effect, from not only the cessation of the state support from Byzantium as a result of the Arab conquest but also the severe destruction from the strong earthquake that hit the area at that time. The intensities of the seismic events that hit the cities were estimated earlier, which are within the range of 8 e9. Our estimates indicate that the PGV values are about 1.5 m/s. Hence, the magnitude of the causative earthquake could be in the range M z 6.5 e7.5, and the location of the epicenter might be at a distance of a few dozens of kilometers from the ancient Rehovot-ba-Negev city, while the other variants associated with the earthquake seem to be less probable.展开更多
The earthquakes with Ms≥6.0 are often gathered into belts or clusters and are roughly consistent with tectonic structure trends in the Sichuan-Yunnan (Chuan-Dian) region. The middle south part(98°-106°E, 21...The earthquakes with Ms≥6.0 are often gathered into belts or clusters and are roughly consistent with tectonic structure trends in the Sichuan-Yunnan (Chuan-Dian) region. The middle south part(98°-106°E, 21°-34°N) of South-North Seismic Zone can be zoned into seven small areas. There all were strong quakes with M_s≥7.0 historically in each small area. Ten earthquakes with M_s≥7.0 have occurred in this region since 1970 and they appeared in five small areas respectively. The relationships between occurrence-time and cumulative frequencies of strong quakes in these five areas are shown to be an exponential distribution or power function. By examining the inner coincidence it is indicated that these relationships are of definite significance to mid-long term macroseismic prediction of each area.展开更多
Macroseismic intensity data plays an important role in the process of seismic hazard analysis as well in developing of reliable earthquake loss models. This paper presents a physical-based model to predict macroseismi...Macroseismic intensity data plays an important role in the process of seismic hazard analysis as well in developing of reliable earthquake loss models. This paper presents a physical-based model to predict macroseismic intensity attenuation based on 560 intensity data obtained in Iran in the time period 1975-2013. The geometric spreading and energy absorption of seismic waves have been considered in the proposed model. The proposed easy to implement relation describes the intensity simply as a function of moment magnitude, source to site distance and focal depth. The prediction capability of the proposed model is assessed by means of residuals analysis. Prediction results have been compared with those of other intensity prediction models for Italy, Turkey, Iran and central Asia. The results indicate the higher attenuation rate for the study area in distances less than 70 km.展开更多
In this paper, according to the data on the middle and strong earthquakes in China, we have preliminary studied the relation between the characteristic of space-time evolution of the seismic apparent strain field and ...In this paper, according to the data on the middle and strong earthquakes in China, we have preliminary studied the relation between the characteristic of space-time evolution of the seismic apparent strain field and the regions of 31 macroseism events since 1955. The result shows that, there is a rather well correlation between the anomaly region of seismic apparent strain and the zone of macroseism event occurrence within the time range of one to about five years. The R value of the application of the abnormal region of seismic apparent strain to predicting the area of strong earthquake occurrence is 0.458, and the empirical possibility of forecasting the region of macroseism occurrence is 0.625, and so the forecasting effect is comparatively well. Finally, the main results obtained above are discussed preliminarily.展开更多
The Ms7.0 Lushan earthquake on April 20, 2013 is another destructive event in China since the Ms8.0 Wenchuan earthquake in 2008 and Ms7.1 Yushu earth- quake in 2010. A large number of strong motion recordings were acc...The Ms7.0 Lushan earthquake on April 20, 2013 is another destructive event in China since the Ms8.0 Wenchuan earthquake in 2008 and Ms7.1 Yushu earth- quake in 2010. A large number of strong motion recordings were accumulated by the National Strong Motion Obser- vation Network System of China. The maximum peak ground acceleration （PGA） at Station 51BXD in Baoxing Country is recorded as -1,005.3 cm/s2, which is even larger than the maximum one in the Wenchuan earthquake. A field survey around three typical strong motion stations confirms that the earthquake damage is consistent with the issued map of macroseismic intensity. For the oscillation period 0.3-1.0 s which is the common natural period range of the Chinese civil building, a comparison shows that the observed response spectrums are considerably smaller than the designed values in the Chinese code and this could be one of the reasons that the macroseismic intensity is lower than what we expected despite the high amplitude of PGAs. The Housner spectral intensities from 16 stations are also basically correlated with their macroseismic intensities, and the empirical distribution of spectral intensities from Lushan and Wenchuan Earthquakes under the Chinese scale is almost identical with those under the European scale.展开更多
基金partial financial support of ISTC grant No. G-2153
文摘An important task in seismic hazard assessment is the estimation of intensity and frequency of rare strong seismic shaking, in particular, the long-term peak ground velocity values(PGVs). A recently proposed method is suitable for simply estimating PGVs based on the examination of the magnitude of displacements of rock blocks. The effectiveness of this method is demonstrated by results of studies on the source zones of two large earthquakes and a vicinity of one strong explosion. In this study, the method is applied to the examination of archeoseismological data from the ancient Rehovot-ba-Negev city and other ancient cities from the Negev desert(in Southern Israel) where numerous evidences of presumable seismic damage were found earlier. The cities and also a sophisticated irrigation system within the region, which existed in the Negev desert, were abandoned however in the middle of the seventh century. The abandonment could be caused by a combined effect, from not only the cessation of the state support from Byzantium as a result of the Arab conquest but also the severe destruction from the strong earthquake that hit the area at that time. The intensities of the seismic events that hit the cities were estimated earlier, which are within the range of 8 e9. Our estimates indicate that the PGV values are about 1.5 m/s. Hence, the magnitude of the causative earthquake could be in the range M z 6.5 e7.5, and the location of the epicenter might be at a distance of a few dozens of kilometers from the ancient Rehovot-ba-Negev city, while the other variants associated with the earthquake seem to be less probable.
文摘The earthquakes with Ms≥6.0 are often gathered into belts or clusters and are roughly consistent with tectonic structure trends in the Sichuan-Yunnan (Chuan-Dian) region. The middle south part(98°-106°E, 21°-34°N) of South-North Seismic Zone can be zoned into seven small areas. There all were strong quakes with M_s≥7.0 historically in each small area. Ten earthquakes with M_s≥7.0 have occurred in this region since 1970 and they appeared in five small areas respectively. The relationships between occurrence-time and cumulative frequencies of strong quakes in these five areas are shown to be an exponential distribution or power function. By examining the inner coincidence it is indicated that these relationships are of definite significance to mid-long term macroseismic prediction of each area.
文摘Macroseismic intensity data plays an important role in the process of seismic hazard analysis as well in developing of reliable earthquake loss models. This paper presents a physical-based model to predict macroseismic intensity attenuation based on 560 intensity data obtained in Iran in the time period 1975-2013. The geometric spreading and energy absorption of seismic waves have been considered in the proposed model. The proposed easy to implement relation describes the intensity simply as a function of moment magnitude, source to site distance and focal depth. The prediction capability of the proposed model is assessed by means of residuals analysis. Prediction results have been compared with those of other intensity prediction models for Italy, Turkey, Iran and central Asia. The results indicate the higher attenuation rate for the study area in distances less than 70 km.
基金The Key Project(95-04-06-03,95-04-07-02)from China Seismological Bureau.
文摘In this paper, according to the data on the middle and strong earthquakes in China, we have preliminary studied the relation between the characteristic of space-time evolution of the seismic apparent strain field and the regions of 31 macroseism events since 1955. The result shows that, there is a rather well correlation between the anomaly region of seismic apparent strain and the zone of macroseism event occurrence within the time range of one to about five years. The R value of the application of the abnormal region of seismic apparent strain to predicting the area of strong earthquake occurrence is 0.458, and the empirical possibility of forecasting the region of macroseism occurrence is 0.625, and so the forecasting effect is comparatively well. Finally, the main results obtained above are discussed preliminarily.
基金supported by Science Foundation of Institute of Engineering Mechanics,CEA under Grant No.2013C03National Natural Science Fund Nos.51308515 and 51278473Nonprofit Industry Research Project of CEA under Grant No.201208014
文摘The Ms7.0 Lushan earthquake on April 20, 2013 is another destructive event in China since the Ms8.0 Wenchuan earthquake in 2008 and Ms7.1 Yushu earth- quake in 2010. A large number of strong motion recordings were accumulated by the National Strong Motion Obser- vation Network System of China. The maximum peak ground acceleration （PGA） at Station 51BXD in Baoxing Country is recorded as -1,005.3 cm/s2, which is even larger than the maximum one in the Wenchuan earthquake. A field survey around three typical strong motion stations confirms that the earthquake damage is consistent with the issued map of macroseismic intensity. For the oscillation period 0.3-1.0 s which is the common natural period range of the Chinese civil building, a comparison shows that the observed response spectrums are considerably smaller than the designed values in the Chinese code and this could be one of the reasons that the macroseismic intensity is lower than what we expected despite the high amplitude of PGAs. The Housner spectral intensities from 16 stations are also basically correlated with their macroseismic intensities, and the empirical distribution of spectral intensities from Lushan and Wenchuan Earthquakes under the Chinese scale is almost identical with those under the European scale.
