volcano history facts

Rank Volcano Year Deaths top 10

1. Tambora, Indonesia 1815 92,000

2. Krakatau, Indonesia 1883 36,417

3. Mount Pelee, Martinique 1902 29,025

4. Ruiz, Colombia 1985 25,000

5. Unzen, Japan 1792 14,300

6. Laki, Iceland 1783 9,350

7. Kelut, Indonesia 1919 5,110

8. Galunggung, Indonesia 1882 4,011

9. Vesuvius, Italy 1631 3,500

10. Vesuvius, Italy 79 3,360
3 types of earthquake waves
p waves

secondary waves

surface waves
the p and s wave are called body waves.

Earthquakes can occur just below the surface or deep below the surface.

FACT: Earthquakes occur in the crust or upper mantle, from the earth's surface to about 500 miles below the surface. Seismologists use earthquakes to study the interior of the earth and to pinpoint faults and geologic structures such as the core-mantle boundary, subduction zones, and the subsurface extent of the San Andreas Fault. Using earthquakes and waves from earthquakes, scientist can see all of the earth’s interior.

The fastest wave, and therefore the first to arrive at a given location, is called the P wave. The P wave, or compressional wave, alternately compresses and expands material in the same direction it is traveling.

Moonquakes (“earthquakes” on the moon) do occur, but they happen less frequently and have smaller magnitudes than earthquakes on the Earth. It appears they are related to the tidal stresses associated with the varying distance between the Earth and Moon. They also occur at great depth, about halfway between the surface and the center of the moon.