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Australia: The Land Where Time Began |
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Gorkha
Earthquake, Nepal – Slip Pulse and Resonance of the Kathmandu Basin
during the 2015 event Understanding of the physics of earthquakes and
associated ground shaking is enhanced by detailed geodetic imaging of
ruptures during earthquakes. This Mw 7.8 earthquake that
occurred on 25 April 2015 is the first large continental megathrust
rupture that has occurred beneath a high-rate (5 Hertz) Global
Positioning System (GPS) network. Galetzka et
al. used the GPS and
interferometric synthetic aperture radar to model the earthquake rupture
as a slip pulse of about 20 km wide, of a duration of about 6 seconds,
which attained a peak sliding velocity of 1.1 m/s, which propagated at
about 3.3 km/s over 140 km toward the Kathmandu Basin. A large
slip-weakening distance, about 5 m, was indicated by the smooth onset of
slip, which caused moderate shaking at frequencies greater than 1 hertz;
peak ground acceleration, about 16 % of the gravity of the Earth, and
minimised damaged to vernacular residences (traditional houses). The
collapse of tall structures, including cultural artefacts, was caused by
whole-basin resonance at a period of 4-5 seconds.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |