摘要
一个大地震的发生是在大区域内地应力长期积累、集中、加强,最后导致应变能突然释放的结果。在应力积累、集中、加强的过程中,必然伴随着地壳形变过程。用大地形变测量方法预测大震的工作应有系统分层次地进行。 大区域地形变监测:应用空间大地测量技术,布设大区域的形变监测网,监测板块运动及一些大构造单元的相对运动,探测太区域应力场、形变场的变化,寻找地应力的集中区。 中区域地形变监测:在划定的应力集中区布设GPS加密网,结合水准复测监视区域应力场、形变场的变化,从中发现地应力的加强部位。 小区域地形变监测:在划定的地应力加强部位,选择一些活断裂带,布设一批高精度的光速测距网、水准网进行加密观测,监视应力场、形变场的中短期变化。 地形变台站监视:在重要的活断裂带和重点监视区布设高精度的地形变台站监视应力场、形变场的短临变化。 按照这四个层次进行观测,将使大震预测在空间上逐级缩小,在时间上逐渐缩短。
The occurrence of a great earthquake is the consequence of stress accumulation, concentration and strengthening over large areas and the sudden release of strain energy at last. The process of stress accumulation, concentration and strengthening must be accompanied by the process of crustal deformation. Earthquake prediction by geodetic means should be carried out systematically and gradually.Crustal deformation monitoring over large areas: Space geodetic techniques can be used for deploying deformation monitoring network over large areas, monitoring plate movements and relative movements in some large tectonic units, detecting variations of large-scale stress field and deformation field and seeking stress concentration areas.Crustal deformation monitoring over medium-sized areas: The GPS densified network can be deployed within the determined stress concentration area. Combined with relevellings, variations of regional stress field and deformation field can be monitord, from which the intensified parts of stress can be found.Crustal deformation monitoring in small areas: Some active faults can be selected in the determined intensified parts of stress to deploy a number of precise geodolite and leveling networks for densified observation and for monitoring the medium and short-term variations of stress field and deformation field.Mornitoring at crustal deformation stations: Crustal deformation stations for monitoring short-term and immediate variations of stress field and deformaion field can be deployed along major active faults and in major monitoring areas.Based on the observations at thses four stages, the predicted range of location and the predicted limits of time for a great earthquake can be reduced gradually.
出处
《地壳形变与地震》
CSCD
1989年第3期93-99,共7页
Crustal Deformation and Earthquake
