19 December 2017

The massive, catastrophic Villa Santa Lucia landslide in Chile: videos and images start to hint at the cause

Posted by Dave Petley

The Villa Santa Lucia landslide: videos and images start to hint at the cause

Over the course of yesterday it slowly started to become clear that the Villa Santa Lucia landslide in Chile on Saturday was an extremely large failure event. The most important image that I have seen to date is this Reuters image of the source zone of the landslide:-

Villa Santa Lucia landslide

Reuters image of the source of the Villa Santa Lucia landslide, via t13cl

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It is worth taking a closer look.  In the image below I have merged the source area from the above image with the pre-failure Google Earth perspective view of the area.  It is a bit clunky, but seems to indicate that this might be a massive failure of a moraine deposit at the glacier snout:-

Villa Santa Lucia landslide

Merged Reuters and Google Earth imagery of the source of the Villa Santa Lucia landslide

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The material involved in the flow appears to be consistent with the landslide being a combination of moraine and material that it has eroded from the hillsides and the channel.  This makes the landslide track about 8 km from the source to Villa Santa Maria:-

Villa Santa Lucia landslide

Approximate locations of the source, track and deposit of the Villa Santa Lucia landslide.

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The best understanding of the track of the landslide comes from this Youtube video, which captures a helicopter flight up the valley from Villa Santa Lucia:-

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The erosion of the channel suggests a very large volume flow, and the super-elevation around the bends suggest high velocities.  I have found one video that captures the impact of the landslide on Villa Santa Lucia:

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The latest news regarding the town of Villa Santa Lucia is that 12 people have been confirmed to have been killed, and a further 14 remain missing.  The operation to recover the victims continues.