Recently, we got the news that the western part of Nepal may be hit by a larger earthquake than that of April 25, because it did release all of its energy. During the earthquake, only the eastern part of Nepal was affected. So I want to know if Kathmandu, i.e. the central part of Nepal, could also be affected by the anticipated earthquake.

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    $\begingroup$ You did not get "the news", you got speculation. Predicting a next quake, where and how strong, is impossible. You can do statistics and give chances at best. Yes, another big earthquake will hit Kathmandu - that can be tomorrow or 50 years from now. Voting to close as 'too broad'. $\endgroup$
    – Jan Doggen
    Aug 8 '15 at 18:30
  • $\begingroup$ I understand what you are implying but all I ask is if this "speculation" also includes Kathmamdu and the eastern part of Nepal. $\endgroup$
    – Rajshree
    Aug 10 '15 at 12:34

The partial release of strain energy makes another major earthquake in the same area less likely - in the near future.

That said, there is not just a single slip plane between the converging Indian and Tibetan tectonic plates. Rather, the nappes (slabs of rock) are stacked about 12 layers deep, with Tibet over-thrusting India at a low angle.

The main Himalayan thrust fault slipped at an average depth of about 8 kilometers. There is still unreleased strain energy accumulating in thrust faults above this level. Geographically, an area 120 kilometers long by 60 kilometers wide slipped three metres southwards and one meter upwards in just over 20 seconds.

The adjacent Himalayan regions, east and west, will eventually rupture in more or less similar manner. Bear in mind that the mean rate of tectonic convergence across the Nepalese Himalayas in the vicinity of Kathmandu is 17.5 +/- 2 mm per year, whereas the overall rate of convergence of the Indian and Tibetan (Eurasian) tectonic plates is between 26 and 36 mm per year.

The Kathmandu earthquake locally released 86 years' worth of strain energy, equivalent to 35 mm per year, so is very unlikely to slip that much again for decades to come. But if I was living in north India, west Nepal or Bhutan, I'd be worried. The recent earthquake was magnitude 7.8 according to seismometers on the Indian side, and magnitude 8.1 according to Chinese seismometers (counter-intuitively both could be right). For those parts of the Himalayas that haven't experienced a major quake for centuries the accumulating strain could be phenomenal. For these areas a magnitude 8.5 is plausible.

  • $\begingroup$ This answer would benefit from some references or links to back up some of the various numbers. $\endgroup$
    – kwinkunks
    Oct 9 '15 at 11:48

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