Ouro Preto: a Brazilian landslide destroys historic houses

I have been writing about landslides in Brazil all week.  To cap it off, videos emerged yesterday of another landslide there, this time in the city of Ouro Preto in Minas Gerais.  In fact, there are two remarkable drone videos, and some additional mobile phone videos, of this event.

The video that has been most widely circulated is this one:-

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But this drone video of the same event is also worth a look:-

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The landslide occurred at 9 am (local time) on 13 January 2022 at Morro da Forca.  Instability in the slope had been noted by local residents, and the site had been cordoned off.  As a consequence there were no casualties, but two buildings dating from the 19th Century were destroyed.  Reports indicate that the failure has followed heavy rainfall, although conditions were dry at the time of the landslide.

Hoje Emdia has this image of the aftermath of the landslide:-

The aftermath of the 13 January 2022 landslide at Ouro Preto in Brazil. Image from Hoje Emdia.

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The second video posted above is interesting.  It shows a series of collapses at the toe of the slope as the main mass destabilises and moves.  The power of even a comparatively small landslide is clearly illustrated by the rapid and complete destruction of presumably well-constructed historic buildings,

Reports indicate that there (rightly) continues to be concern about the potential for a further failure at this site.  The area remains cordoned off.  There are concerns about the historic buildings on the other side of the street, which include a hotel, a restaurant and the Arts and Convention Center of the Federal University of Ouro Preto (UFOP).

Given the age of the buildings, this slope had presumably been stable for many decades after the initial building works.  It would be interesting to know if any modifications to the slope had been conducted in recent years.

Finally, the image above suggests to me that in the upper part of the scarp the landslide might have mobilised existing planes of weakness, but this remains to be confirmed.

Brazil often receives heavy rainfall at this time of the year, and landslides are common.  This year appears to have been quite bad again.