A paper has recently been published in the journal Landslides<\/em><\/a> (Kusumawardani et al.<\/em> 2021<\/a> – you should be able to read the paper here<\/a>) that examines one of the largest of these events, the landslide at Petobo in Palu.\u00a0 Just this landslide alone caused the destruction of about 3,300 houses and almost 2,000 people lost their lives.<\/p>\n The paper is a detailed description arising from a site reconnaissance.\u00a0 It is a very valuable catalogue of the features observed, accompanied by a high quality interpretation of them.\u00a0 This, for example, is an interpretation of the movement vectors of the observed features on the ground.\u00a0 These are remarkable given that the average slope gradient is just 2\u00b0.<\/p>\n Movement vectors for the landslide at Petobo in Indonesia. Figure from Kusumawardani et al.<\/em> (2021)<\/a>.<\/p><\/div>\n .<\/p>\n Kusumawardani et al.<\/em> (2021)<\/a> have revisited the issue of the cause of the Petobo landslide.\u00a0 They have considered carefully the role of the irrigation canal near to the crown of the landslide – note that this can be seen on the image above.\u00a0 The authors note that the unlined canal was constructed around 110 years ago.\u00a0 It had been upgraded through time but was unlined, and thus would have been charging the local groundwater levels.\u00a0 Prior to the earthquake the canal was full, and that it was being used to flood the local paddy fields to a depth of 30 to 50 cm.<\/p>\n![\"Movement](\"https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/07\/21_07-Petobo-1.jpg\")