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A submarine, undersea, or underwater earthquake is an earthquake that occurs underwater at the bottom of a body of water, especially an ocean. They are the leading cause of tsunamis. The magnitude can be measured scientifically by the use of the moment magnitude scale and the intensity can be assigned using the Mercalli intensity scale.
A tsunami earthquake can be defined as an undersea earthquake for which the surface-wave magnitude M s differs markedly from the moment magnitude M w, because the former is calculated from surface waves with a period of about 20 seconds, whereas the latter is a measure of the total energy release at all frequencies. [2]
Tsunamis can occur when an underwater earthquake rapidly displaces massive amounts of water, leading to a large, long wave that builds in intensity as it crosses the ocean. When it reaches land it ...
The 2004 Indian Ocean tsunami was a teletsunami.. A teletsunami (also called an ocean-wide tsunami, distant tsunami, distant-source tsunami, far-field tsunami, or trans-ocean tsunami) is a tsunami that originates from a distant source, defined as more than 1,000 km (620 mi) away or three hours' travel from the area of interest, [1] [2] sometimes travelling across an ocean.
Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthquakes are the planet's most powerful, with moment magnitudes (M w) that can exceed 9.0.
Many researchers have chased clues of the last “big one”: an 8.7-magnitude earthquake in 1700. ... “The recurrent interval for this subduction zone for big events is on the order of 500 ...
About 55 earthquakes a day – 20,000 a year – are recorded by the National Earthquake Information Center. A quick guide to how they are measured. ... You can get TurboTax for 30% off on Amazon ...
Historically, the most recent large-scale earthquake to occur in the Nankai Trough was in 1944 off the Kii Peninsula. Using recent ocean bottom seismograph studies, it has been determined that most of the seismicity occurs near the trough axis (Obana et al., 2006).