While supervolcanic eruptions can cause global destruction, they are rare.
Both earthquakes and volcanic eruptions release tremendous energy onto the planet with the potential of causing almost unmatched destruction. There are 1,500 active volcanoes on the Earth as of 2010, according to Live Science, and over a million earthquakes occur every year--though they are not always felt. One of the largest earthquakes in recorded history occurred in the United States and the biggest volcano in the world is on American grounds.
Earthquake and Volcano Basics
Volcanoes occur when molten rock, called magma, breaks through a weak part of the Earth's crust. Volcanoes often build up mountains as ash and lava accumulate in layers on the surface.
Earthquakes are sudden movements of the earth's surface; the planet's rigid crust breaks and snaps into a new position when the stress of tectonic forces is greater than the rocks' strength. The seismic waves (or vibrations) generated from the break travel through along the earth's surface, causing the movements known as earthquakes.
Biggest and Baddest
The largest volcanic eruption ever observed and recorded was in Indonesia. Mount Tambora on the island of Sumbawa erupted in 1815, killing 100,000 people.
The largest known recorded earthquake occurred in Chile in 1960. Measuring 9.5 on the Richter scale, it killed 6,000 people, many of whom died from the resulting tsunami that traveled as far as Hawaii and Japan. The most destructive recorded earthquake is believed to have occurred in China in 1556, in which approximately 830,000 individuals perished.
Biggest and Baddest in the United States
Hawaii's Mauna Loa volcano is not only the largest volcano in the United States, it is the largest in the world at 13,000 feet elevation. The islands of Hawaii themselves were created by "hot spots," or massive pockets of magma that well up from deep within the earth.
Alaska experienced the largest recorded earthquake in the United States, at 9.2 on the Richter scale. It killed 115 people and raised and lowered the ground in some places by as much as 56 feet.
Average Activity
While supervolcanic eruptions so massive they can cause climatic change do occur, this only happens every 100,000 years or so, according to experts at Live Science. More common are small volcanic eruptions, like many of the the 33 eruptions that have occurred on Mauna Loa since 1843, or milder activity, such as at Kilauea (also on the Hawaiian islands), which has been continually erupting since 1983.
On average, there is only one "great" earthquake annually, or one that measures at least 8.0 on the Richter scale. Approximately 18 "major" earthquakes, or those measuring 7.0 to 7.9 on the Richter scale, occur yearly. Over 900,000 earthquakes measure 2.9 or lower every year.
Effects
Volcanic eruptions can make sunsets more colorful thousands of miles away. In 2001, Alaska's Kasatochi volcano erupted, spreading fine ash particles into the atmosphere and scattering the sun's rays. People from around the world reported unusually stunning sunsets in shades of orange and coral, according to Live Science.
Contrary to a popular myth, earthquakes do not cause volcanoes. However, forces associated before, during and after a volcanic eruption can set off an earthquake.
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