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龙门山断裂带上的汶川地震摧毁了四川的几座城市,夺去了69000多人的生命。计算结果显示,该地震可能使部分鲜水河断裂、东昆仑断裂大部以及部分岷江断裂应力增加了0.2～0.5bar,更加接近破裂状态。这3条位于青藏高原东部的活动断裂带均在离汶川发震带150～400km的库仑静应力影响范围内。由于部分受力断层上的应变累积至少已有一个世纪之久,最近的汶川地震有可能触发或加速这些断层带上新的7级以上强震的发生,从而可能造成从四川省康定至道孚、青海省玛沁至甘肃省洛大以及邻近区域的强烈震动。本文利用由计算得到的汶川地震引起的应力变化以及过去10年观测到的背景地震发生率,对该地区在未来10年内发生破坏性地震的概率以及可能的空间分布进行了预测。结果表明,研究区内在未来10年内发生M≥6级地震的概率为57%～71%,发生M≥7级地震的概率为8%～12%,是汶川地震前发震概率的2倍。
The Wenchuan earthquake on the Longmenshan fault zone destroyed several cities in Sichuan and claimed more than 69,000 lives. The calculation results show that the earthquake may increase the stress of some Xianshuihe faults, most of the east Kunlun fault and part of the Minjiang fault to 0.2 ~ 0.5 bar, which is closer to the rupture state. The three active fault zones located in the eastern part of the Qinghai-Tibet Plateau are all within the range of Coulomb’s static stress of 150 ~ 400 km away from the Wenchuan earthquake zone. Due to the accumulation of strain on some stressed faults, the recent Wenchuan earthquake may trigger or accelerate the occurrence of new strong earthquakes of magnitude 7 or above on these fault zones, which may result in the occurrence of strong earthquakes from Kangding in Sichuan Province to Daofu , Qinghai Province, Maqin to Gansu Province, Luo and the nearby area of strong vibration. Based on the calculated stress changes caused by the Wenchuan earthquake and the background earthquakes observed in the past 10 years, this paper predicts the probability and the possible spatial distribution of the destructive earthquakes in the next 10 years in this area. The results show that the probability of occurrence of M≥6 earthquakes within the next 10 years is 57% ~ 71% in the study area, and the probability of occurrence of M≥7 earthquakes is 8% ~ 12%, which is twice that of the Wenchuan earthquake.