Abstract In Kashmir Himalaya, the Medlicott-Wadia Thrust is a main active fault responsible for the crustal accretionary prism building during the Late Quaternary. Because of the long seismic silence during the last five centuries, it is a key structure to be studied in order to estimate the regional seismic hazard. In the Riasi area, the analysis of two paleoseismological trenches allowed us identifying and measuring several seismic ruptures over the last ~3500 years. We determined that the oldest rupture occurred around 1600–1000 BC, while the youngest occurred after 1470 AD. The latest event is compatible with the great 1555 AD (Mw > 7.5) Kashmir earthquake, whose evidence at the surface had not yet been recognized. Our results show that despite the long-lasting seismic gap, the Medlicott-Wadia Thrust is a main seismogenic structure in the region, able to produce large earthquakes. Their recurrence interval ranges between 500 and 700 years, implying that a main seismic event could occur in the next decades. These seismic ruptures are localized over gently-dipping fault branches associated with decameter-scale scarps. The morphologies observed are due to a significant non-localized component of the deformation in Quaternary sediments.

中文翻译：

---

克什米尔喜马拉雅地震裂隙中大型古地震的复发（印度里亚西地区）

摘要 在克什米尔喜马拉雅山，梅德利科特-瓦迪亚逆冲断层是晚第四纪地壳增生棱柱体形成的主要活动断层。由于过去五个世纪的长时间地震沉默，它是评估区域地震危险性的关键结构。在 Riasi 地区，对两个古地震海沟的分析使我们能够识别和测量过去约 3500 年的几次地震破裂。我们确定最古老的破裂发生在公元前 1600-1000 年左右，而最年轻的发生在公元 1470 年之后。最新的事件与公元 1555 年（Mw > 7.5）克什米尔大地震兼容，其地表证据尚未得到确认。我们的结果表明，尽管存在长期的地震间隙，Medlicott-Wadia 断层是该地区的主要地震构造，能够产生大地震。它们的重现间隔在 500 到 700 年之间，这意味着未来几十年可能会发生一次主要的地震事件。这些地震破裂位于与十米级陡坡相关的缓倾断层分支上。观察到的形态是由于第四纪沉积物中显着的非局部变形成分造成的。