关键词: 南北地震带, 强震迁移, 南亚地震带

Abstract: Migration of strong earthquakes(M≥7) along the North-South Seismic Belt since 1500 AD shows three patterns: roughly similar time and distance interval migration from N to S, multi-pattern migration from S to N and clusters of strong earthquakes occurring in some periods within the whole seismic belt. Based on analysis of strong earthquakes in the past hundred years, the activity of the North-South Seismic Belt is related to the strong earthquake activity of the South Asia Seismic Belt elongating from Burma to Sumatra, Indonesia. Strong earthquakes along the former belt often occur several months or years after the quakes on the later belt. The above-mentioned migration characteristic of strong earthquakes is likely caused by the northward collision and subduction of the India Plate as well as coaction between the Qinghai-Tibet Plateau and the stable and hard Ordos and Alashan Massif at the northeastern margin of the Plateau. The South-to-North migration of strong earthquakes with different time intervals and different migrating rates may directly reflect the uneven, irregular pushing of the northeastern corner of the India plate, and the gradually northward transmitting and expanding of the related stress as it accumulates and strengthens. While the North-to-South migration of strong earthquakes with long time intervals and uniform rate may relate to the movement of the further deeper materials, or to the interaction between the strongly-deformed Qinghai-Tibet Plateau and the northern hard massif. Perhaps it results from the successive, north-to-south, lateral-slipping and rotational-twisting movement of the strip massifs constituting the Qinghai-Tibet Plateau. As for the phenomenon that strong earthquake clusters occur constantly in a certain time on the North-South Seismic Belt, it may imply that the deformation induced by India Plate indenting strongly into Eurasia continent on the eastern margin of the Qinghai-Tibet Plateau has been strengthened. And the clustering of strong earthquakes on North-South Seismic Belt and South Asia Seismic Belt also confirms that the northern collision zone and the eastern subduction zone of India Plate, as a whole, have impact on the activity of the earthquakes on the Chinese North-South Seismic Belt and Burma, Andaman till Sumatra.

Key words: the North-South Seismic Belt, migration of the strong earthquakes, the South Asia Seismic Belt