Birthday wish: measure Everest... 2015 2015 Nepal earthquake may have moved Mount Everest

G.S. Mudur, TT, New Delhi, Jan. 24:  India's oldest government science agency is set to celebrate its 250th anniversary this year through an expedition to measure the height of Mount Everest amid speculation that the 2015 Nepal earthquake may have moved the peak.

The Survey of India (SOI) will use modern satellite-linked instruments and traditional trigonometry to determine the peak's altitude which is currently documented through multiple surveys at 8,848 metres (29,029 feet) above sea level, the Surveyor General of India, Swarna Subba Rao, said.

"We're hoping to send the expedition this year, we've got the required approvals, but we haven't decided on dates yet," Rao told The Telegraph.

The April 2015 earthquake of magnitude 7.8, epicentred northwest of Kathmandu that pulled down structures and buildings across the country and killed over 9,000 people, had stirred speculation in scientific circles on its impact on the Himalayas and Mount Everest.

Some wondered whether the tectonic jolt had pushed Everest higher. But data from a satellite-linked instrument that Chinese scientists had installed in 2005 suggested that Mount Everest was neither taller nor shorter, Lisa Wald, a US geophysicist wrote on the US Geological Survey website. "Instead, the motion on the fault had shifted the entire mountain three cm to the southwest, leaving the height of the mountain still at 8,848 metres," Wald wrote.

Rao said the SOI expedition seeks to set at rest speculation about the peak's post-earthquake height.

"This is a primary reason for our planned expedition," Rao said. "But the Survey of India also celebrates its 250th year in 2017, and we thought that measuring Everest would be a befitting exercise among other technical activities we're planning," he said.

Mount Everest was first granted the title of the world's highest peak in 1856 after nearly two years of observations by SOI scientists and others. Since then, many agencies have measured the height of the mountain's peak with consistent results.

The new Everest-measurement exercise will rely on two techniques - some scientists will climb the peak and use global positioning system (GPS) instruments to measure its altitude, while others will use high-school trigonometry techniques to measure the altitude from surrounding locations in the Himalayas.

Rao said members of the planned Everest expedition will be staff scientists of the SOI, an organization created in 1767 primarily to map the subcontinent for the East India Company. It remains the country's principal mapping agency.

Scientists say that while it would be interesting to wait for the results of India's planned new measurements, satellite-based surveillance provides superior readings compared to traditional measurements.

"Using instruments aboard satellites, we can make extremely fine measurements down to millimetre level accuracy which are better than traditional methods," Wald told this newspaper.