基于大量SAR数据的时序InSAR技术已被广泛应用于断裂带震间长期缓慢地壳形变的观测研究，文中对现有多种时序InSAR方法（如Stacking，PSInSAR，SBAS等）的基本原理和技术特点进行了概括总结。采用PSInSAR技术，利用2003—2010年的17景降轨ENVISAT/ASAR数据，在海原断裂带中段开展了震间地壳形变观测的实验研究，获得了海原断裂中段的跨断层InSAR形变速率场整体图像，显示了约5mm/a的左旋走滑运动速率，与GPS和地质学研究基本一致。在此基础上，对时序InSAR断层活动性观测研究中的若干问题，如LOS形变速率与目标断层走向的关系、LOS 形变速率与跨断层观测宽度的关系、LOS 形变速率与GPS等其他形变速率的关系以及LOS 形变速率场揭示的断层相互作用及断层滑动方式等进行了分析探讨。这些将为进一步推进InSAR构造变形监测研究提供参考。

In the past few years, the improved InSAR technology based on time series analyses to many SAR images has been used for measurement of interseismic deformation along active fault. In the paper, we first made a summary and introduction to the basic principle and technical characteristics of existing Time Series InSAR methods(such as Stacking, PSInSAR, SBAS). Then we presented a case study on the central segment of Haiyuan Fault in west China. We attempt to use the PS-InSAR(Permanent Scatter InSAR)technique to estimate the motion rate fields of this fault. We processed and analyzed 17 scenes of ENVISAT/ASAR images in descending orbits from 2003-2010 using the PS-InSAR method. The results reveal the whole movement pattern around the Haiyuan Fault and a remarkable velocity gradient of about 5mm/a across the central segment of the fault. The motion scenes are consistent with left-lateral strike-slip. On this basis, we make a discussion on some issues about observation of fault activity using Time Series InSAR methods, such as the changes of LOS deformation rates with fault strike and region width observed across a fault, fault reciprocity and motion style indicated by Time Series InSAR rate map and the relationship between the InSAR LOS deformation and the ones from other methods. All these studies will benefit the promotion of InSAR application in detection of tectonic movement.

Depending on reservoir characteristics and depth, oil or gas production can induce surface subsidence or, in the cases of EOR and CCS, ground heave, potentially triggering fault reactivation and in some cases threatening well integrity.Mapping the surface effects of fault reactivation, due to either fluid extraction or injection, usually requires the availability of hundreds of measurement points per square km with millimeter-level precision, which is time consuming and expensive to obtain using traditional monitoring techniques, but can be readily obtained with InSAR data. Moreover, advanced InSAR techniques developed in the last decade are capable of providing millimeter precision, comparable to optical leveling, and a high spatial density of displacement measurements over long periods of time, without the need for installing equipment or otherwise accessing the study area.Until recently, a limitation to the application of InSAR was the relatively long revisiting time (24 or 35 days) of the previous generation of C-band satellites (ERS1-2, Envisat, Radarsat). However, a new generation of X-band radar satellites (TerraSAR-X and the COSMO-SkyMed constellation), which have been operational since 2008, are providing significant improvements. TerraSAR-X has a repeat cycle of 11 days, while the joint use of two sensors of the COSMO-SkyMed constellation have an effective repeat cycle of just 8 days. With the launch of the fourth satellite of the constellation, in 2010, COSMO-SkyMed will have an effective revisiting time of just 4 days, allowing "near real-time" applications. Indeed, by combining two acquisition geometries (e. g. data acquired along ascending and descending orbits), it will be possible, on average, to have a new scene over the area of interest every other day.Additional advantages of the new X-band satellites are: a higher sensitivity to target displacement and a higher spatial resolution (the density of measurement points can be increased by an order of magnitude, possibly exceeding 2,500 PS/km(2)).In this paper, we present some examples of the application of X-band SAR data to reservoir monitoring. Special attention will be given to CCS projects where InSAR data could become a "standard" monitoring tool. The paper will highlight the technical features of the new sensors, the possible synergy between TerraSAR-X and COSMO-SkyMed data, as well as the importance of a careful analysis of atmospheric disturbances affecting SAR data covering the area of interest, in order to retrieve high quality displacement data. Finally, some conclusions will be drawn supporting recommendations about future CCS monitoring programs. (C) 2010 Published by Elsevier Ltd.]]>

城市范围内直下型活动断裂突发错动产生的直下型大地震,直接威胁城市和人民生命财产的安全.城市活动断裂探测和地震危险性评价是为城市减灾服务的一项系统工程,也是活动构造研究面临的一项新的工作.这一工作的核心是要解决城市范围内的断裂定位、断裂最新活动、断裂的深部背景、断裂的地震危险性和地面错动危险性及减灾对策.为了更好地理解这一问题,作者用"有没有、活不活、深不深,震不震,错不错,好对策"这6句话来表示其核心内容.文中对这些问题作了具体的说明.

Displacements along active faults buried directly beneath major cities create devastating earthquakes that seriously threaten the safety of human lives and properties. Exploration and seismic hazard assessment of active faults in urban areas are thus an important systematic engineering for disaster mitigation in major cities. It is also a new field for active tectonic studies. The kernel of this work includes determining of the exact location of active faults, dating the ages of last tectonic activity, relating the shallow level faults to structures in the crustal depth, assessing seismic hazard and potential for surface offsets, and formulating countermeasures for disaster mitigations. We use the following simple phrases to express these key scientific problems: Where are the faults? Are they active? How deep are they? Will they create earthquake? Will they form surface offsets? What are the countermeasures? This paper explains these key scientific problems in detail.

中国东部城市地区大多为较厚第四系松散物覆盖区,许多城市附近发育了具有相当规模的隐伏断裂。在这些第四系较厚覆盖区发育的隐伏断裂的上断点是否代表了断裂的最新活动时代?文中通过对邢台、唐山等发生过强震的中国东部城市附近地区地质、地球物理、地震活动、地形变等资料的综合分析,来讨论这些较厚第四系覆盖区隐伏断裂的上断点与断裂的最新活动年代的关系问题。初步分析表明,作为邢台地震和唐山地震发震断裂的新河断裂和唐山断裂带,并不象其上断点显示的为晚更新世不活动断裂或者为局部活动段,而均为大型活动断裂。由此认为,在中国东部沉积层较厚地区,不能完全根据断裂断错的最新地层确定断裂的最新活动时代。对于一条穿过新沉积较厚地区的断裂,其最新活动时代应根据构造背景、断裂对新地层的控制作用、断错最新地层、新地层沉积厚度、构造地貌、地震活动、地形变、现今构造应力场等综合判定。

The urban area in the eastern China region is mostly covered by the relatively thick loose Quaternary deposits,below which,in many cities,there exist many considerably large buried faults.In these thick-Quaternary-covering areas,does the date of the upper layers dislocated by the buried faults represent the latest faulting? In this paper,based on the integrated analysis on the data of geology,geophysics and earthquakes of cities in the east of China,including Xingtai and Tangshan,we discussed the relation between the upper offset point and the latest activity times of the buried faults in these areas covered by thick Quaternary.Our study shows,in the area with very thick recent deposits in East China,one should not determine the latest faulting of one fault fully according to the younger layers displaced by the fault.To a fault running through the area covered with thick young deposits,its latest active period should be determined comprehensively by the tectonic settings,the controlling of the fault to the young strata,the youngest layer displaced by the fault,the thickness of the young deposits,seismicity and modern tectonic stress field,etc.

The Tangshan area lies in the North China plain where an Ms 7.8 earthquake occurred in 1976, which is associated with a hidden active fault. To reveal the recurrence characteristics of major quakes in this area over a relatively long time, we have conducted a comprehensive study using geological investigations, shallow seismic exploration, boreholes, trench observations and geological dating. Five paleoearthquakes were recognized in a 6.4m-deep trench west to the Tangshan Asylum. Among them, the former three events occurred between 56.78 +/- 4.83ka and 89.39 +/- 7.60 ka, and the fourth event occurred around 6.9 ka, respectively, and then followed by the fifth in 1976. Seven boreholes were deployed crossing the ground fissure formed by the 1976 Tangshan earthquake at the site of No. 10 Middle School, where we have identified 25 liquefaction events in the boreholes TZC65 and 67. By the comprehensive analysis of the trench, the liquefaction events from the boreholes and the depth-time curves of drill cores, we suggest a new recurrence model of major quakes in this area. It is not a constant recurring cycle since 210 ka, instead consisting of six alternating seismically quiet and active stages. Of them, stage I (>177 ka) was a quiescent period in seismicity, stage II (from 143 ka to 177 ka) was an active one, stage III (from 102 ka to 143 ka) was quiescent again, stage IV (from 56 ka to 102 ka) had many quakes, stage V (from 6.9 ka to 56 ka) became quiet, and stage VI (from 6.9 ka to now) was the beginning of a new seismically active period.