Richter scale- measures amplitude of earthquakes

The Richter scale measures the amplitude of earthquakes. The Richter scale is logarithmic, which means that each number is ten times larger in amplitude than the previous one. For example, a 7 is ten times as large as a 6. 2 is the smallest amplitude felt.

• M=1 to 3: Recorded on local seismographs, but generally not felt
• M=3 to 4: Often felt, no damage
• M=5: Felt widely, slight damage near epicenter
• M=6: Damage to poorly constructed buildings and other structures within 10's km
• M=7: "Major" earthquake, causes serious damage up to ~100 km (recent Taiwan, Turkey, Kobe, Japan, and California earthquakes).
• M=8: "Great" earthquake, great destruction, loss of life over several 100 km (1906 San Francisco, 1949 Queen Charlotte Islands).
• M=9: Rare great earthquake, major damage over a large region over 1000 km (Asian Tsunami Earthquake 2004,Chile 1960, Alaska 1964, and west coast of British Columbia, Washington, Oregon, 1700).

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