InSAR analysis of a blind thrust rupture and related active folding: the 1999 Ain Temouchent earthquake (M w 5.7, Algeria) case study     

Samir Belabbès  Mustapha Meghraoui  Ziyadin Çakir  Youcef Bouhadad 《Journal of Seismology》2009,13(4):421-432

We study the surface deformation associated with the 22 December 1999 earthquake, a moderate sized but damaging event at Ain Temouchent (northwestern Algeria) using Interferometric Satellite Aperture Radar images (InSAR). The mainshock focal mechanism solution indicates reverse faulting with a NE–SW trending rupture comparable to other major seismic events of this section of the Africa–Eurasia plate boundary. Previously, the earthquake fault parameters were, however, poorly known because no aftershocks were precisely determined and no coseismic surface ruptures were observed in the field. Using a pair of ERS data with small baseline and short temporal separation in the ascending orbit we obtained an interferogram that shows the coseismic surface displacement field despite poor coherence. The interferogram measures four fringes and displays an ellipse-shaped lobe with ∼11 cm peak line-of-sight displacement. The elastic modeling using a boundary element method (Poly3Dinv) indicate coseismic slip reaching up to 1 m at 5 km depth on the N 57° E trending, dipping 32° NW Tafna thrust fault. The geodetic estimate of seismic moment is 4.7 × 10¹⁷ N m. (Mw 5.7) in is good agreement with seismological results. The elliptical shape of the surface displacement field coincides with the NE–SW trending Berdani fault-related fold. The consistency between the geological observations and InSAR solution shed light on the precise earthquake location and related Tafna fault parameters.  相似文献   

A note on the M w 6.3 earthquake in Iceland on 29 May 2008 at 15:45 UTC     

R. Sigbjörnsson  J. Th. Snæbjörnsson  S. M. Higgins  B. Halldórsson  S. Ólafsson 《Bulletin of Earthquake Engineering》2009,7(1):113-126

This preliminary study aims to investigate a M _w 6.3 earthquake that occurred in South Iceland on Thursday 29 May 2008 at 15:45 UTC. The epicentre was in the Olfus District between the towns of Selfoss and Hveragerdi. This study examines the data recorded and the damage observed immediately after the event. Horizontal accelerations of up to 80%g were recorded in the epicentral region and there is visual evidence that the vertical acceleration exceeded 1 g. The PGA data is compared to a ground motion estimation model developed for the South Iceland earthquakes in June 2000. In general the basic properties of this event are found to be similar to the characteristics of the South Iceland earthquakes in June 2000. The duration of strong-motion is short and the intensity attenuates rapidly with increasing distance. The earthquake action resisted by buildings in the near fault area is inspected through evaluation of elastic as well as inelastic response spectra. The vast majority of structures seemed to withstand the strong-motion fairly competently and without significant visual damage due firstly to the low-rise, predominantly reinforced concrete or timber, style of buildings. Secondly, the short duration of strong-motion contributed to the endurance of structures.  相似文献   

福建台网“九五”“十五”观测系统测定震级对比研究     

蔡杏辉  陈惠芳 《山西地震》2009,(4):3-8

运用福建台网“九五”“十五”两套观测系统的资料,对两套系统测定的震级及“十五”系统测定的速度震级和仿真震级进行对比分析,得出,两套系统的震级偏差基本在观测规范允许范围之内;“十五”系统的速度震级与仿真震级偏差分布不集中,一致性较差;为“九五”与“十五”系统过渡提供参考依据。  相似文献   

单台地震观测报告震相数据的验证方法探讨     

杨世英  孟彩菊  赵春华  靳玉贞 《山西地震》2009,(4):35-36

简要介绍了利用电子走时表和网上地震目录对单台地震观测报告的震相数据进行初步检查的方法及其软件实现,认为,利用该方法可找出观测报告中分析错误和误差较大的震相,可作为一种对单台地震观测报告进行检查的有效方法。  相似文献   

山西流体观测井水位与气压相关性分析   总被引：2，自引：0，他引：2  

刘国俊  杨海祥  黄春玲  王向阳  张文男  李民  刘晓萍 《山西地震》2009,(2):7-10,30

分析了山西省流体观测井水位动态特征,利用高阶差分、回归分析方法计算了2008年山西省各观测井水位与气压相关系数,得到了气压系数的背景值,进而对气压干扰因素进行定量化的排除,并对各井的气压系数进行对比分析。结果表明,不同的观测井孔水位受气压影响程度不同,对于某一个观测井孔而言,气压系数及相关系数的变化是有一定规律的。  相似文献   

山西大同市地震应急基础数据库项目建设现状及改进对策分析     

李秀英 《山西地震》2009,(4):46-48

文章通过对大同市地震应急基础数据库项目建设的现状,数据收集的过程进行分析,发现了目前存在的问题,进一步提出了改进的措施和建议,明确应建立各项管理制度,确保地震应急基础数据库在地震发生后发挥其作用。  相似文献   

南海北缘海啸波高对潜在海啸源震级偏差的敏感性     

任鲁川  薛艳  简春林  冯蔚 《中国地震》2009,25(2)

本文假设马尼拉海沟北段为潜在海啸源,基于中国地震台网对马尼拉海沟地区震级测定偏差,采用COMCOT(comell Multi-grid Coupled Tsunami Model)海啸数值模型,模拟南海海啸波传播.选取南海北缘3个特定地点,其中两个位于华南近海区域,另一个位于台湾岛南端近海区域,此外还在临近马尼拉海沟北段的深海地区选取了1个特定地点.分析这些特定地点最大海啸波以及最大海啸波到时对于震级测定偏差的敏感性.结果表明:马尼拉海沟北段地震如触发海啸,华南近海区域以及台湾岛南部近海区域最大海啸波振幅对震级偏差敏感,但最大海啸波振幅到时对于震级测定偏差不敏感;振幅最大的海啸波,二十几分钟即可波及台湾岛南端近岸区域,大约1小时后波及大陆华南近海北部区域.  相似文献   

2008年10月5日新疆乌恰6.8级地震现场考察     

陈建波  谭明  寇大兵  胡伟华  高国英  杜春清  侯建盛  李志强  赵保宗  张天罡  宁宝坤 《中国地震》2009,25(4)

2008年10月5日在新疆乌恰地区发生的M_S6.8地震,微观震中位于乌恰县境内,距边境18km,宏观震中位于吉尔吉斯斯坦共和国努拉村,距新疆乌恰县伊尔克什坦口岸西南约7km处,极震区烈度达到8度(境外).我国境内Ⅶ度和Ⅵ度区面积分别为7354km~2和1031km~2.这次地震的发生与南北向的卡兹特阿尔特弧形断裂带的活动有关.震区建筑物遭到一定程度的破坏,地质灾害现象较明显.  相似文献   

攀枝花6．1级地震前的气氡异常分析     

邱桂兰  张晋川 《四川地震》2009,(2):26-30

2008年8月30日,攀枝花市与西昌市会理县交界处发生了6．1级地震,在这次地震前,攀枝花川-05井的数字气氡出现了明显的异常变化。综合分析认为,气氡观测存在短期、临震异常的同时,还存在中期趋势异常。本文主要对8月30日地震前,气氡观测资料的异常、机理及有关问题进行了分析和讨论。  相似文献   

Variability in rainfall threshold for debris flow after the Chi-Chi earthquake in central Taiwan, China   总被引：6，自引：0，他引：6  

C. L. SHIEH  Y. J. TSAI 《国际泥沙研究》2009,24(2):177-188

The purpose of this study is to analyze variability in rainfall threshold for debris flow （critical rainfall for debris flow triggering） after the ML 7.3 Chi-Chi earthquake in central Taiwan in 1999. Two study sites with different geological conditions were surveyed in the earthquake area. Streambed surveys were conducted to continuously monitor debris flows between 1999 and 2006. During the 7-year study period, every debris flow event was identified, and the streambed characterized. Results show that the rainfall threshold for debris flow was remarkably lower just after the Chi-Chi Earthquake, but gradually recovered. To date, this rainfall threshold is still lower than the original level prior to the earthquake. This variability in rainfall threshold is closely related to the mount of sediment material in the initiation area of debris flow, which increased rapidly due to landslides resulting from the earthquake. With the increase in sediment material, the rainfall threshold was lowered severely during the first year following the Chi-Chi earthquake. However, heavy rainfalls mobilized the sediment material, causing debris flows and transporting sediment downstream. With the decrease in sediment material, the rainfall threshold recovered gradually over time. Furthermore, debris flows occurred only in the subbasins that had sufficient sediment material to cause significant movement. Hence, these results confirm that the sediment material in the initiation area of debris flow is a crucial component of the rainfall threshold for debris flow.  相似文献