A revised landslide map for the M=7.8 Kaikoura earthquake

Valkaniotis Sotiris of the Earthquake Geology Research Group and the Aristotle University of Thessaloniki has posted a revised map of the landslides triggered by the M=7.8 Kaikoura Earthquake in New Zealand on his blog.  This map is available as a high resolution download:

Map of Co-seismic ruptures and landslides from the M=7.8 Kaikoura earthquake in New Zealand

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To generate this map, which shows 5,875 landslides is a remarkable effort.  The maps of the density of landslides is particularly interesting to me:

Map of landslide density from the M=7.8 Kaikoura earthquake, via Valkaniotis Sotiris

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I noted in my earlier post that a reasonable first order estimate of the landslide locations can be obtained from the coincidence of the topography and the aftershock sequence.  This is a map of the aftershocks from the earthquake, mapped as a KML by Geonet.

Geonet / GNS data showing the locations of the aftershock sequence triggered by the M=7.8 Kaikoura earthquake, mapped on Google Earth

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The coincidence between the two is not perfect of course (we would not expect it to be)  but the aftershocks are a surprisingly good predictor of the landslide distribution.  It would be interesting to know whether the aftershocks are a better predictor than the ShakeMap peak ground acceleration data.  The map produced by Valkaniotis Sotiris hints that this might be the case.

Other posts that might be of interest:

• Geonet commentary on landslides triggered by the Kaikoura Earthquake
• Kaikoura earthquake landslides: the picture slowly emerges
• First news of landslides from the Kaikoura Earthquake sequence in New Zealand yesterday
• Hapuku River: a major landslide dam after the earthquake in New Zealand
• Comparing initial landslide reports: Tumbi Quarry, Papua New Guinea and Kaikora, New Zealand
• Landslides from the 2015 Wilberforce earthquake in New Zealand
• UBC distinguished lecture powerpoint file: Earthquake-induced landslides – lessons from Taiwan, Pakistan, China and New Zealand