14 April 2010
This morning’s Mw=6.9 earthquake in China is now reported to have killed at least 300 people, with the toll likely to rise over the next few hours. Although the earthquake occurred in an area with a low population total and density, vulnerability of both buildings and the landscape to shaking is likely to be high, especially given the reported shallow nature (depth = 10 km) of the event.
The Google Earth imagery of the area shows a landscape that is sparsely populated with substantial mountains such that landslides may well be a serious issue.
The landscape appears to vary, with rolling hills in the south (image from here):
To the north the landscape is undoubtedly steeper and more rugged, and thus landslide-prone: (image from here)
The town in the foreground above is Jiegu (sometimes spelt Gyegu). Early reports suggest that up to 80% of the buildings in the town have been destroyed. Images of the town before the earthquake suggest that it is likely to have been very vulnerable both to ground shaking and to landslides:
Given the remoteness of this area, and the likelihood of landslides on the roads, the delivery of aid is going to be a major challenge. My earlier comments on the reporting of large earthquakes in mountain areas applies here once again (insert China for Haiti):
1. Everything stops at night. At the time of writing it is still night time on Haiti. In the aftermath of an earthquake electricity and power supplies are wiped out, so for the night time period it appears that the disaster is not as bad as is feared. As the sun comes up so the reports on the true picture start to emerge, and the fatality statistics start to increase rapidly. This increase will continue for several days at least, but may ultimately exceed the final toll;
2. The initial focus is often wrong. In the immediate aftermath of a disaster the initial focus of the media reports is often on the biggest city. This is rarely where the biggest impact has occurred, but it is most accessible so will be the focus of the reports.
3. No news is very, very bad news. The biggest impacts are often in rural areas with the highest levels of shaking. These areas had poor communications to start with, but when an earthquake strikes the roads become blocked, power is lost and there is no telephone service. Therefore, no news comes out for some time after the quake. The picture is actually the opposite of the obvious. If news starts to emerge quickly from those areas with the highest shaking then the picture is not as bad as we feared – at least some communications are open – although it may still be quite grim. If there is almost no news at all from the rural areas for a day or two, then the picture is probably very bad indeed, with almost all of the communications wiped out.
4. The media focus will quickly change to the foreign rescue teams. However, although these efforts are valuable, their overall impact is very small. The real work is actually done by local people – most rescues are made by untrained people in the first 24 hours – this should really be the focus.