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1942 Wairarapa Earthquake
Two 1942 Wairarapa earthquakes shook the lower North Island of New Zealand; on 24 June and 2 August. They were large and shallow with epicentres close together east of Masterton in the Wairarapa region. The June earthquake was sometimes referred to as the Masterton earthquake but both caused damage over a wide area, from Dannevirke and Eketahuna over to Whanganui and down to Otaki, New Zealand, Otaki and Wellington, New Zealand, Wellington. There was one death in Wellington, on 24 June. The August earthquake can be regarded as an aftershock of the June earthquake. Both earthquakes were preceded by smaller foreshocks. As the second quake was slightly less in magnitude than the first, they were not an earthquake doublet where the second quake is slightly larger. The August earthquake was considerably deeper (40 km, not 12 km), though another source gives the depths as 43 km and 15 km. There was another large aftershock on 2 December and one in February 1943. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moment Magnitude Scale
The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 paper by Thomas C. Hanks and Hiroo Kanamori. Similar to the local magnitude scale, local magnitude/Richter scale () defined by Charles Francis Richter in 1935, it uses a logarithmic scale; small earthquakes have approximately the same magnitudes on both scales. Despite the difference, news media often says "Richter scale" when referring to the moment magnitude scale. Moment magnitude () is considered the authoritative magnitude scale for ranking earthquakes by size. It is more directly related to the energy of an earthquake than other scales, and does not saturate—that is, it does not underestimate magnitudes as other scales do in certain conditions. It has become the standard scale used by seismological authorities like the U.S. Geological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |