Chivay: another valley-blocking landslide in the Arequipa region of Peru

At 7:30 am on 9 May 2021 a valley-blocking landslide occurred immediately upstream of the town of Chivay in the Arequipa region of Peru.  There are news reports about this event on both Prensa National and Inforegion.  They report that the landslide is about 300 m long (but see below), blocking the Rio Colca and allowing a lake to form.  The Prensa National report has the best image I have found so far:-

The 9 May 2021 valley-blocking landslide at Chivay in Peru. Image from Prensa National.

.

I have marked the location of the Chivay landslide on the Google Earth image below.  The location is: -15.627°, -71.598°:-

Google Earth image showing the location of the 9 May 2021 valley-blocking landslide at Chivay in Peru.

.

The landslide can be seen on Planet Labs imagery captured in recent days, although unfortunately the resolution does not provide much detail of the failure itself:-

Satellite image showing the location of the 9 May 2021 valley-blocking landslide, and the barrier lake, at Chivay in Peru. Image copyright Planet Labs, captured on 10 May 2021, used with permission.

.

I have highlighted the landslide on the image, but note that it appears to be smaller than  the news reports indicate. The barrier lake is clearly visible upstream of the landslide dam.  At the time that the image was collected it appears to have been about 1 km long.  Images collected yesterday suggest that the barrier had not yet breached.

Whilst the town in immediately downstream of the barrier, the news reports indicate that the risk is not considered to be high at this point.  Nonetheless there are plans to construct a channel to allow the lake to drain.

This area was affected by the larger 18 June 2020 Achoma landslide less than a year ago.   The landslide dam there was successfully drained.

.

Reference

Planet Team (2021). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/