Predicting the distribution of major debris flow hazard using coupled 10Be erosion records and 1m resolution digital topography

2010年8月6日，强烈的风暴在印度河流域引发了广泛的泥石流，集中在印度莱赫附近。最初有3000多人下落不明，最终死亡人数超过200人，600多所房屋被毁。我们的团队已经在该地区工作了十多年，我们于2011年5月访问了该地区，重新调查和重新采样了我们拥有事件前数据的通道。我们发现，泥石流集中在山前附近，有点出乎意料：山前附近的渠道是低救济冲积扇表面，而在高山的主要渠道是深深的切割，乍一看似乎更活跃。然而，我们注意到，靠近山前的山坡比集水区的高海拔部分更粗糙（岩石更多），而且更多地被切割;泥石流就是从这些粗糙的、被切割的山坡起源的。我们认为，粗糙的山坡与泥石流活动，并试图测试这一假设与泥石流通道和以前无法获得的高分辨率地形数据的详细实地调查相结合。我们还将量化，如果泥石流的空间分布持续了很长的时间尺度，通过测量流沉积物中的10 Be的浓度。这些测量和我们的分析将有助于我们了解喜马拉雅山及更远地区偏远山区的泥石流危害。

On the 6th of August 2010 intense storms triggered widespread debris flows in the Indus Valley centred near Leh, India. Initially over 3000 people were unaccounted for and the final toll was over 200 dead and over 600 houses destroyed. Our group has been working in the area for over a decade and we visited the area in May 2011 to resurvey and resample channels where we had pre-event data. We discovered that debris flows concentrated near the mountain front, somewhat contrary to expectations: channels near the mountain front are on low relief alluvial fan surfaces whereas in the high mountains the main channel is deeply incised and would appear at first glance more active. However, we noted that the hillslopes near the mountain front were rougher (rockier) and were more dissected than the high elevation portions of the catchment; it is from these rough, dissected hillslopes that the debris flows originated. We believe that the rough hillslopes correlate with debris flow activity and seek to test this hypothesis with a combination of detailed field surveys of debris flow channels and previously unavailable high resolution topographic data. We will also quantify if the spatial distribution of debris flows persists over long time scales by measuring the concentration of 10Be in stream sediments. These measurements and our analysis will help us to understand debris flow hazard in remote mountainous areas in the Himalayas and beyond.