Hawaii is well known for its volcanic hazard, but the islands are also susceptible to major earthquakes such as a magnitude 7. Evidence of prehistoric quakes is hard to come by in Hawaii, making it especially difficult to guess when the next big one will strike. The Hawaiian Island chain was formed by a massive plume of extra-hot magma rising through the molten mantle between Earth's crust and core.
The plume forced its way through the ocean crust, creating a volcano. As the Pacific plate slowly moved over the stationary plume, new volcanic islands were formed as older ones went dormant — the Big Island is where the magma is currently breaking through. Loading the ocean crust with massive volcanoes — the from ocean floor to peak, the Big Island is the tallest feature on — causes it to flex, which can produce earthquakes. Even more dangerous are the quakes caused by the expansion of the volcano as new magma pushes out from below.
These jolts can be very large and cause destructive tsunamis as well. More than half of the people killed by the died in the ensuing tsunami. With only the historical earthquake record to go by, scientists have little data to help them estimate the probability of another big quake in the future.
The most recent giant quake was a magnitude 7. Does this mean Hawaii can relax for another 70 years or so? It's impossible to say. And since , there have been seven quakes of magnitude 6. Hawaii is fortunate that most of its biggest earthquakes occur on the relatively sparsely populated Big Island. And the most active part of the Big Island is the south flank, which would send a tsunami out to sea instead of toward the other islands.
But big ones that do sometimes strike the west flank of the island could send a tsunami to the much more populated shores of Maui and Oahu. In the past, some of the earthquakes caused by the flexing of the crust under the weight of the islands have struck near Maui, including a magnitude 6. And Hawaii has plenty of older buildings that won't survive major shaking, particularly many homes that are not bolted down to a solid foundation.
Image: Damage to the Hawaii Volcano Observatory after a magnitude 6. Senior Editor Twitter. Topics Earth Science Geology. The greater humidity in the eastern half of the country causes these processes to happen faster so that evidence of fault lines is erased much faster than in the West. Some of the best evidence of strong prehistoric earthquakes in the CEUS is from liquefaction features sand boils and dikes that are forced to the surface by ground shaking.
Despite these problems and shortcomings, the distribution of historical earthquakes and the geologic evidence of prehistoric earthquakes provide a reasonable guide to the seismic hazard in much of the CEUS.
The good news is that much more data has been collected in recent years, particularly in and around the New Madrid Seismic Zone. A magnitude 5. A magnitude Skip to main content. Search Search. Each type is the outcome of different forces pushing or pulling on the crust, causing rocks to slide up, down or past each other. Strike-slip faults indicate rocks are sliding past each other horizontally, with little to no vertical movement.
Both the San Andreas and Anatolian Faults are strike-slip. Normal faults create space. Two blocks of crust pull apart, stretching the crust into a valley.
Reverse faults , also called thrust faults, slide one block of crust on top of another. These faults are commonly found in collisions zones, where tectonic plates push up mountain ranges such as the Himalayas and the Rocky Mountains. Strike-slip faults are usually vertical, while normal and reverse faults are often at an angle to the surface of the Earth. World Map - Most Populated Countries by Major Museums of the World.
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