【摘要】 在青藏高原北部地区活动地块划分的基础上,以地块为研究单元,对1970年以来的b值进行全时空扫描,以研究其短临时间特征,结果表明,虽然受地域和地质构造的影响,各地块b值的短临异常与5级地震的对应率不同,但绝大多数地块的b值正、负异常起始时间、最大(最小)值时间和结束时间通常出现在震前1～6个月内。对其结果统计检验,本地块R≥R975.%的合格率为93%,内邻地块合计R≥R97.5%的合格率为100%,可信度检验率较高。更多还原

【Abstract】 Based on the division of active blocks in the northern Qinghai-Tibet plateau,the spatial and temporal scan for b,-value of small earthquakes in every blocks since 1970 was made to study the short-impending anomaly characteristics. The result indicates that in most areas,the starting time,ending time and maximal or minimal value of the positive and negative anomalies of b,-value appear one to six months before the medium,-strong earthquakes although the ratios of the b,-value anomalies corresponding to MS?Y5.0 earthquakes are different in the different blocks, owing to the variations of the regionally geological structures. And the result is checked up statistically by using R,-value . The eligible rate(R?YR97.5%) in the region is 93% ,and the general eligible rate of R-value for inner and adjacent regions is 100%.??The reliability rate is very high.更多还原