We evaluate the seismotectonic setting in the Upper Assam and Arunachal/Bhutan segments to obtain a critical understanding of the 1950 earthquake, and its predecessors. The paleoseismological findings from the region inform that among the earthquakes prior to 1950, the one that occurred either in 1697 or in 1714, may belong to the class of a major earthquake (M~8), and it may have activated part of the Bhutan-Arunachal segment. The Assamese historical reports are much vocal on the effects of the 1697 earthquake (known as the Sadiya earthquake) in the Upper Assam Valley than that of the 1714 event. The evidence provides more credence to the 1697 event that may tentatively be given the status of a major earthquake in the Upper Brahmaputra region, and the 1714 event appears to be more of a Bhutan-specific event. The geological record indicates that the great Upper Assam earthquake of 1950 does not have any predecessors mimicking its magnitude nor the projected complex style of rupture at least during the last 1000 years or may be more. The question is whether the 1950-type earthquake involving two orthogonal structures with variable strain accumulation is kinematically a repeatable activity. The 1697 earthquake with a likely magnitude (M_w) of ≥8 must have ruptured the eastern-most part of the Arunachal frontal thrust. The records from the Assam Valley do not conclusively establish the evidence of any major impact in the Brahmaputra Valley, commensurating with a magnitude ≥8.0 assigned to the 1714 event sourced in the Bhutan segment.

我们评估了上阿萨姆邦和阿鲁纳恰尔/不丹段的地震构造环境，以获得对 1950 年地震及其前身地震的批判性理解。该地区的古地震研究表明，在 1950 年以前的地震中，发生在 1697 年或 1714 年的地震可能属于大地震（M~8）级，它可能激活了不丹的部分地区。 -阿鲁纳恰尔段。阿萨姆人的历史报告对 1697 年阿萨姆河谷上游地震（称为萨迪亚地震）的影响比 1714 年事件的影响要大得多。证据为 1697 年的事件提供了更多可信度，该事件可能暂时被认为是上布拉马普特拉河地区的大地震，而 1714 年的事件似乎更像是不丹特有的事件。地质记录表明，1950 年的上阿萨姆大地震没有任何模仿其震级的前兆，也没有至少在过去 1000 年或更长时间内预测的复杂破裂类型。问题是 1950 年型地震涉及两个具有可变应变积累的正交结构，在运动学上是否是可重复的活动。1697 年的地震，震级可能为 (M_w ) ≥ 8 一定已经破裂了阿鲁纳恰尔锋冲断层的最东端。来自阿萨姆河谷的记录并没有最终确定雅鲁藏布江河谷有任何重大影响的证据，与分配给不丹段的 1714 事件的震级 ≥ 8.0 相称。