The loss of life from seismic landslides

May 12 — the third anniversary of the devastating earthquake Venchuanskogo, also known as Sichuan. In honor of this sad date of Chengdu University of Technology organized a conference on the problem of landslides induced by earthquakes. My presentation will be held in the morning session and the main focus of it is on the loss of life from landslides caused by earthquakes. I will also mention our journal Nature Geoscience, leaving on Sunday, in the discussion regarding the mass balance in the mountain range. I also write about this interesting issue in the blog.

Question deaths also mentioned the PDF-document, dosupnom this link: 11_05 China keynote Petley blog

Below I will try to describe the key aspects of the performance.

Regular readers know that one of the aspects of my research is to collect data on landslides that killed people. I've been doing this since September 2002, and periodically publish the data in this blog. In the presentation of the data evaluated with emphasis on seismic landslides. During the period from September 1, 2002 on December 31, 2010 I have recorded nearly 82,000 killed in landslides. The information shown in the chart:

It can be seen that the dominant growth deaths associated with two earthquakes — in Kashmir in 2005 and Wenchuan in 2008. Unfortunately, the exact number is not on the Kashmir earthquake. Approximately can be established that there were killed by landslides 26,400 people. As a result of the same processes at Venchuanskom earthquake killed 20,000.

Interestingly, the increase in the number of deaths from landslides caused by rains, proceeds linearly:

The combined plot of seismic landslides reveals two splashes of large catastrophes, but actually happened in this period 32 earthquake that caused fatal landslides:

This implies that more than 50% of people killed by landslides for the period studied, died as a result of landslides caused by earthquakes. Specifically, it shows the importance of what we need to better understand yavlyaeniya provoked by earthquakes.

The data collected by me (black dots) may be combined with information obtained from the literature (white dots) to get an initial assessment of the number of deaths due to landslides with the magnitude of the earthquake. The spread of values is large, but we can define two threshold levels. Orange line marks the limit of 90% of the events, and the red line is limited to all events have occurred:

This is only a preliminary analysis that requires further work.

Finally, the greatest increase in deaths from landslides observed in the aftermath of earthquakes, which is understandable. After reviewing data from Sichuan Province before and after the earthquake, I have noted a significant increase in deaths due to landslides after the disaster:

As can be seen, after the earthquake occurred the death of another 300 people in a shorter period. Interestingly, there has been a marked increase in the number of serious landslides, but only an increase in the number of fatalities each landslide. This may mean that I can not register the weaker landslides in the aftermath of the earthquake:

All of this information is intended to show that the data do not allow us to estimate the real consequences of landslides. The actual loss is undoubtedly much higher, but I have to stress that in case of serious earthquake victims counting accuracy is not high.

Translation: Vitaly Semkin
Source: American Geophysical Union

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