19 September 2011

Update on the earthquake in India, Nepal, Bhutan and Tibet

Posted by dr-dave

As expected, the news emerging from India, Tibet, Nepal and Bhutan is of increasing losses from the earthquake yesterday, and of considerable disruption from landslides.  It does appear that the timing of the event at the end of the monsoon has increased landslide impacts, exacerbated by ongoing heavy rainfall in the area.  The combination of this rainfall and ongoing aftershocks is likely to render the recovery operations very challenging indeed.  Expect the losses to creep upwards during the day as remote areas are slowly accessed.  Unfortunately, the weather forecast for the area is poor:

Widespread rainfall would occur over Sub Himalayan West Bengal & Sikkim and fairly widespread over Gangetic West Bengal during next 48 hours.
Isolated heavy to very heavy rainfall would occur over Sub Himalayan West Bengal & Sikkim and isolated heavy over Gangetic West Bengal during next 48 hours.

The impact of the earthquake appears to be as follows, based on reports that are slowly emerging from the affected countries:

Bhutan

The area of Bhutan affected by the earthquake is very isolated, so reports are quite sketchy at present.  Kuensel online reports:

Full extent of damage not known due to a partial collapse of the communication system…While no casualties have been reported so far in Bhutan, cracks to buildings were reported in some parts of the country.  In Thimphu, the referral hospital’s emergency ward saw three trauma cases, and two cases of disjointed shoulders of people who had fallen during the tremor.

Some landslides have been reported away from the main affected area:

A massive landslide in Phuentsholing buried a Spark car, which was on its way to the hospital. The driver managed to escape.

And

..four roadblocks caused by falling debris reported on the Chukha – Phuentsholing road.

Given the distance that these sites are from the epicentre, we are likely to see much more profound damage in the northwest.  It may well be another 24 hours before the real picture in Bhutan becomes clear.

India

Several news reports in India point to the impact of landslides, and the role that they are playing in hampering the rescue efforts.  For example, Indian Express notes that:

Rain and landslides were blocking rescue efforts of hundreds of workers searching for survivors of a 6.8 magnitude earthquake that jolted a remote the north and northeastern India, killing at least 40 people…Around 400 personnel of National Disaster Response Force (NDRF) and a team of 20 doctors, sent to Sikkim for rescue and relief operations, have not been able to yet reach the quake-hit areas due to blockade of roads following landslides, officials said today.

Meanwhile, the loss of life to date appears to be about 36 people, including 25 in Sikkim and a further 11 in Bihar and West Bengal.

Nepal

Nepal News reports eight fatalities in Nepal, and many more injured. This includes three people killed when the boundary wall of the British Embassy in Kathmandu collapsed into the road (an absolute tragedy for all involved); one person killed by falling debris in  Bhaktapur; two people were killed in Dharan in a house collapse; one person killed by falling debris in Dhankuta; and one death in Sankhuwasabha.  Notably there is comparatively little information about the far northeast of the country.

Tibet

Xinhua reports seven fatalities in Tibet, and 22 people injured, all in the border region of Yadong County.  It also reports that:

The earthquake has caused hundreds of landslides that have disrupted traffic, power and water supplies, as well as telecommunications in Yadong County, Tibet”.

Indeed, the news report is accompanied by this image of clearance operations:

 

http://news.xinhuanet.com/english2010/china/2011-09/19/c_131146663_2.htm

 

Synthesis

As expected (but not widely appreciated) landslides are proving to be a major issue in this area in the aftermath of the earthquake. It should be possible to ascertain the approximate extent of the area of landsliding from the distribution of the aftershocks (following the method of Tatard and Grasso 2011), but so far I cannot find a good aftershock map or dataset (anyone know of one?).

This event is undoubtedly very sad, but perhaps most importantly should serve as a wake-up call to the magnitude of the seismic risk in the Himalayas.  This earthquake is much smaller, and in a much less densely populated area, than the large event that we fear in the Himalayas.  It is surely time to make a major effort to build resilience to such an event in this area.

Comments and updates welcome.