Landslides triggered by the 2015 Mw 6.0 Sabah (Malaysia) earthquake: inventory and ESI-07 intensity assignment

Landslides triggered by the 2015 Mw 6.0 Sabah (Malaysia) earthquake: inventory and ESI-07 intensity assignment

21/11/2022 Perigeo 0
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On 4 June 2015, a Mw 6.0 earthquake occurred in the Sabah region (Malaysia), triggering widespread landslides. The study area shows a lower seismicity than surrounding regions: Figure 1 shows the regional seismicity, while Figure 2 presents a closer view on the study area.

Figure 1: regional seismicity, data are from the IRIS earthquake browser.
Figure 2: close view on the seismicity of the study area, data are from the IRIS earthquake browser.

The earthquake triggered thousands of landslides along the slopes of Mt. Kinabalu, the first UNESCO heritage site in Malaysia. In a new paper published in NHESS I provide an inventory of 5198 landslides triggered by the earthquake and I analyze their spatial pattern. The full dataset is available here.

Figure 3: 3D view of the triggered landslides, Google Earth image.

Then, I applied the Environmental Seismic Intensity (ESI-07) scale, which is an intensity scale based exclusively on effects on the natural environment. In order to assign an ESI-07 value to each landslide, I needed to convert the mapped area to volume: I tested several published relations, showing that the quality of input data is far more important than the choice of the scaling relation in driving the final result. Overall, I assign an epicentral ESI-07 intensity of IX; such figure agrees well with a dataset of global earthquakes.

Figure 4: Grid maps of ESI-07 local intensity obtained by adopting different area–volume scaling relations (a: Guzzetti et al., 2009; b: Larsen et al., 2010, all types; c: Larsen et al., 2010, bedrock; d: Larsen et al., 2010, soil; e: Xu et al., 2016; f: Benjamin et al., 2018; g: Caputo et al., 2018); (h) frequency of cells belonging to the different ESI-07 classes for each scaling law.

I personally believe that the scientific communities dealing with the realization of earthquake-triggered landslide inventories and with the documentation of damage using the ESI-07 scale are working on different aspects of the same issue. The methodological workflow presented in the paper may foster a closer collaboration, which should be beneficial for both the communities.

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