INSAR (Interferometric Synthetic Aperture Radar) is a new technique developed in the last decade. It has a non-replaceable application potential in observing vertical deformation of ground surface. It would provide entirely new means and method for monitoring the dynamic field of earthquake. In the SAR images acquired, not only the intensity information but also the phase information of surface features has been recorded, which is an advantage unparalleled by optical remote sensing. Using phase information, the INSAR technique may provide digital elevation model and information on surface deformation. The algorithms of INSAR and D-INSAR (Differential INSAR) are introduced in this paper in details. This new technique has been applied to the study of Mani, Tibet earthquake of Nov. 11, 1997. For detecting the characteristics of deformation produced by Mani earthquake, we have collected three ERS-1/2 SAR images of Mani area, two of which (May 20,1996 and May 21,1996) are tandem mode data (1 day repeat) before Mani M_S 7.9 earthquake in 1997, one of which (April 21,1998) after the earthquake. We used three pass interferometric mode to process the images. First, we used May 20 and May 21,1996 images by making interferometric processing, and extracting the DEM of the studied area. Then, we used May 21 ,1996 and April 21,1998 images by making differential interferometric processing, and removing the effect of terrain obtained from DEM. At last, we detected co-seismic surface displacement of Mani earthquake by D-INSAR technique. The results show that the surface deformation caused by Mani earthquake occurred along NEE direction, and the length of surface rupture is at least more than 70km. Around epicentral area, the width of deformation field in S-N direction is wider than that in other areas. It is determined that the maximum elevation in this area is 98cm, while the maximum subsidence is 95cm. The co-seismic horizontal displacement of the fault is about 5m.

On the basis of previous studies of other researchers, we propose a new approach to detect present-day activities of faults using remote sensing. We have studied the dynamic changes of ground temperature around the epicenter before and after the Mani M_S7.9 earthquake of 1997. It is found that an anomalous increase of ground temperature occurred at the east section of the of Altyn Tagh fault 20 days before the event. Then this anomalous area expanded gradually, formed a remarkable belt which remained till the occurrence of the M_S7.9 earthquake. After the event this belt of anomaly was fading away, while such an anomaly appeared on the seismogenic fault-the Margaichace fault as late as two days before the Mani M_S7.9 event. The evolution process of the image shows that there is some corresponding relationship between the Mani earthquake and evident activity of the Altyn Tagh fault. It also indicates the interaction between the two faults mentioned above as well as the close relation among the deformation anomaly, present-day fault activity and earthquakes. In addition, we propose improvement of the technique for the requirement of the study on present-day activity and interaction of faults.

We have used some new techniques to study the modern eruption scale of the Tianchi Volcano in Changbaishan Mountain. They include analysing the remote sensing data, GIS, multisource data fusion, orthogonal cross-course wavelet transform and the BP neural network method. The geological investigation and dating data are incorporated in the analyses. The results will be helpful for the volcanic hazard assessment.

We present some kinds of satellite remote sensing data which are are often used and their characters. The fusion methods at some levels for different types of remote sensing data and other geoscience data are expounded. It is demonstrated by several application samples that the data fusion methods are helpful to make the characteristic informtion of geology be more prominent.