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2009 Samoa Earthquake And Tsunami
The 2009 Samoa earthquake and tsunami took place on 29 September 2009 in the southern Pacific Ocean adjacent to the Kermadec-Tonga subduction zone. The submarine earthquake occurred in an extensional environment and had a moment magnitude of 8.1 and a maximum Mercalli intensity of VI (''Strong''). It was the largest earthquake of 2009. The earthquake initiated with a normal-faulting event with a magnitude of 8.1. Within two minutes of the earthquake rupture, two large magnitude 7.8 earthquakes occurred on the subduction zone interface. The two magnitude 7.8 earthquakes had a combined magnitude equivalent to 8.0. The event can be considered a doublet earthquake. Normal and thrust faulting triggered a tsunami which caused substantial damage and loss of life in Samoa, American Samoa, and Tonga. The Pacific Tsunami Warning Center recorded a rise in sea levels near the epicenter, and New Zealand scientists determined that the waves measured at their highest on the Samoan coast. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault (geology)
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
