Berg Adventures Everest fall update and quake study re-run: 60% of the Himalaya due for an earthquake
The picture shows Roger Bilham next to the Kala Patar site that is running at 18300' with the summit of Everest towering above Kala Patar, more than 2 miles higher and 3 miles to the East. The South Col site is to the right of the summit (south) and at 26000', 1.5 miles above Kala Patar.' Image courtesy of Berg Adventures 2003 expedition.
11:17 pm CST Nov 06, 2005
Berg Adventures report to ExWeb that they have postponed their Everest expedition to next fall. There are still spots available if you would like to experience the mountain in an unusual way - alone and silent. This autumn, only one expedition made a (short-lived) attempt on Everest and no expedition touched the South slopes at all. In fact, Everest has not been summited in fall since snowboarder Marco Siffredi's disappearance there on September 8, 2002.
This story however, touches another recent subject. In 2003, the Berg team was part of a project involving setting a GPS up at the South Col in cooperation with Roger Bilham, a professor at the University of Colorado, Boulder.
The GPS project had to do with the movement of the Himalayas. Berg sent us a report from Roger himself about how the GPS was being used - to measure the tectonic movement and resultant earthquakes. Here goes a rerun:
Everest - a Mountain of Science By Roger Bilham
"This year's (2003 ed note) climb carries out the most recent, and possibly most important of a series of measurements started almost a decade ago on Mt. Everest. The measurements will determine precisely how fast Everest is rising. The rate of rise is linked to the relation between tectonic plate collision and the productivity of earthquakes under the Himalaya.
As part of the measurements of the height of Everest initiated by Brad Washburn with National Geographic Society backing, four measurements of height were undertaken between 1995 and 1999. In each of the years the precise height and position of a steel bolt on the South Col was measured using GPS methods to an accuracy of roughly 3 mm. This bolt, along with the entire bulk of Everest and the northern Himalaya, is moving towards Beijing at roughly 1 mm each week. More importantly points to the north are moving slightly slower and points to the south slightly faster.
Most recent of these giant earthquakes occurred near Everest in 1934
Thus a region from 20 miles south to 20 miles north of Mt. Everest is being compressed by approximately 3/4" each year. Just as a rubber eraser is thickened when squeezed, so too are the mountains thickening. The net effect is that because of the plate tectonic approach of India and Tibet, Mt. Everest is rising by about 1/4"/year. The precise rate of rise tells scientists the thickness of the layer being squeezed, and this is related to the amount of elastic energy in the Greater Himalaya.
This stored elastic energy is released during an earthquake. The largest Himalayan earthquakes release as much energy as a 100 Megaton bomb. The most recent of these giant earthquakes occurred near Everest in 1934 (The Bihar/Nepal M=8.2 earthquake). While we do not expect this particular region to experience a similar earthquake for many years, we anticipate that both Sikkim and western Nepal may be overdue for great earthquakes. In fact more than 60% of the Himalaya may be ready for a great earthquake.
The big squeeze
We do not know when these large events will occur. We do know, however, that they have occurred in the past, and that they are an inevitable part of the future of the Himalaya. This is not good news for the more than 100 million people of the Himalaya and northern India who live in the threat of these large earthquakes. There has not been a Magnitude 8 earthquake for the past 53 years, and there is thus no general awareness of the seriousness of the seismic threat. Certainly, when one of the 3 or more overdue Richter M>8 Himalayan earthquakes occur there will be a staggering loss of life, and a corresponding economic loss.
After a gap of four years, the 2003 measurement would indicate Everest's rate of rise to better than 1 mm/year. Together with measurements of the changed positions of points to the north and south of Everest the expedition was be able to calculate precisely where the earthquakes are occurring beneath the mountain, and the rate at which Everest is being squeezed, that in turn providing a measure of the rate of accumulation of earthquake energy that will be released in some future earthquake. Calculations show that much of the increase in height is lost during the earthquakes because most of the energy released is indeed elastic. I.e Everest rises between earthquakes and sinks during them.
The expedition compared the height of the South Col relative to the height of Kala Patar, and the heights of these relative to the heights of Kathmandu, Bangalore and Lhasa to an accuracy of a few mm.
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