Abstract:

This study attempted to acquire information of tectonic activity in Western China from the data of the land surface temperature (LST) field. Based on the established relationship between heat and strain, we have analyzed the LST distribution in Western China using the satellite data product MODIS/Terra. The result shows that there are departures of annual changes of LST in some areas, which are associated with activity of some active tectonic zones. After removal of the annualchange background values caused by climatic factors, the longperiod component （LSTLOW） of the residual annual change（ΔT） of the LST can reveal better the tectonic activity, and serve as its indicator. It is found that one major earthquake can produce different effects on the LST fields of broad areas surrounding or even far away from the epicenter, characterized by rise or drop of temperature. For example, a most noticeable temperature decline associated with the Indonesia M 9 earthquake of 2004 appeared in the Bayan HarSongpan Block of the central Tibetan Plateau. On the other hand, the LST field of one area may have different responses to different major shocks in the regions surrounding China. For instance, the East Kunlun M 81 event has made the LST on the Longmenshan fault zone increase, whereas the Zaisangbo M 7.9 earthquake of 2003 and the Indonesia M 9 event of 2004 caused decrease of LST on the Longmenshan. The temporal variations of LST are different in different tectonic areas, which may provide clues for the study of tectonic deformation processes. In combination of data of ground temperature at varied depths, seismicity and GPS measurements, we have checked the information of tectonic activity derived from variations of the LST field, and discussed its implications to the models of regional tectonic deformation.

Key words: Land surface temperature (LST) field, northsouth seismic zone (NS seismic zone), Bayan HarSongpan Block, presentday tectonic activity, earthquake