18 September 2011

First news – the earthquake in India, Nepal and Bhutan this afternoon

Posted by Dave Petley

At 12:40 UT (18:40 local time) today an earthquake struck Sikkim in northern India, producing significant shaking in Nepal, India and, probably Bhutan.  According to the USGS information page for the event, this is a magnitude 6.9 event at a depth of about 20 km, though note that this will probably change slightly as better data become available.  The epicentre is located as shown on the map below:

Although this event occurred sufficiently far to the north to be in a lightly populated area, there may be a not inconsiderable level of loss associated with this event.  The earthquake was sufficiently shallow that the peak ground accelerations may be quite high, and we might expect substantial topographic amplification and other site effects.  In addition, the buildings and infrastructure in this area are highly vulnerable, and landslides are a substantial problem.  Furthermore, the timing of the event, in the late stages of the monsoon, may well mean that the ground is already wet, making landslides more likely.

At the time of writing, some loss information had come in, but given that it is now night-time in this area, and communication links are likely to be highly disrupted, this should not be seen to be a guide to the true level of damage.  News reports from the area suggest 16 fatalities so far, but again this should not be considered to be a reliable guide to the likely level of loss.

Two resources that people may find useful are:

1. The recent report that we wrote about building resilience to earthquakes in rural Himalayan populations, and the need to build resilience (this study was undertaken in north Nepal);

2. The wonderful Save the Hills blog, which documents landslides in Darjeeling.

I’ll blog later as more info becomes available.  Comments and thoughts welcome.  My work email is not working, but I can be contacted on: d.n.petley@googlemail.com