NEW DELHI: The entire Himalayan arc is about to produce a sequence of major earthquakes, and the next major earthquake, of magnitude 8 or greater, may occur during our lifetimes, according to a study reviewing geological, historical and geophysical data.
The human cost of such an event in densely populated countries across the arc is likely to be unprecedented, the researchers said.
The study notes that the sequence of future Himalayan earthquakes could be similar to the large earthquakes that occurred in the 20th century along the Aleutian subduction zone, which stretches from the Gulf of Alaska to Kamchatka in the Far East. Russian.
The review, which appeared in the journal Seismological Research Letters in August, used basic geological principles – stratigraphic analysis, structural analysis, soil analysis, and radiocarbon analysis – to estimate the size and timing of prehistoric earthquakes and assess future risk.
“The entire Himalayan arc that stretches from the eastern limit of Arunachal Pradesh (India) in the east to Pakistan (in the west) has been the source of major earthquakes in the past,” study author Steven G told PTI. Wesnousky.
“These earthquakes will happen again and, scientifically, it would not be a surprise that the next big earthquake It happened in our lives. But the resolution of our studies is, at best, on the order of 100 years, longer than a human lifetime, “said Wesnousky, professor of geology and seismology and director of the Center for Neotectonic Studies at the University of Nevada in Reno, USA.
Seismologist Supriyo Mitra noted that the research is consistent with previous studies.
“The research is a comprehensive review of paleoseismological studies of past Himalayan earthquakes and a forecast of future events based on the findings,” said Mitra, a professor in the department of Earth sciences at the Indian Institute of Education and Scientific Research (IISER) Kolkata.
“The Himalayan faults, as shown in the document, are poised to produce an earthquake of magnitude 8 or more. So yes, we are looking at a big one in the future. No one can say how far from now,” Mitra said, Who it was is not participating in the study, he told PTI.
Previous studies have examined the rate of stress build-up that is occurring across the Himalayan arc from satellite observations.
In the latest study, the timing and size of the most recent prehistoric earthquakes were defined from geology.
The methodology directly applies geological principles to define the past size and timing of earthquakes recorded by sediments broken and deformed by earthquake offsets at sites along the Himalayan front thrust, Wesnousky said.
Satellites can help find the location of active seismic faults, but cannot provide any information about the past time and size of earthquakes on those faults, he said.
“These observations taken together tell us that enough stress has built up over virtually the entire arc to again produce large earthquakes as we see in the geologic record,” Wesnousky explained.
The main cities along and near the Himalayan front push include Chandigarh and Dehradun in India; and Kathmandu, Nepal.
A strong and damaging tremor in such large earthquakes could spread south to India’s capital Delhi, one of the world’s largest cities with a population of more than 11 million, Wesnousky added.
North India has seen many small earthquakes in the last four months, sparking popular speculation about a large one in the region.
However, he said, scientists have yet to find a systematic relationship between the occurrence of small earthquakes and the timing of larger earthquakes in the future.
“These small earthquakes are thousands of times smaller than the large earthquakes we are studying,” he said.
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