Lewis
Member
Richter magnitudes Description Earthquake effects Frequency of occurrence
Less than 2.0 Micro Microearthquakes, not felt. About 8,000 per day
2.0-2.9 Minor Generally not felt, but recorded. About 1,000 per day
3.0-3.9 Often felt, but rarely causes damage. 49,000 per year (est.)
4.0-4.9 Light Noticeable shaking of indoor items, rattling noises. Significant damage unlikely. 6,200 per year (est.)
5.0-5.9 Moderate Can cause major damage to poorly constructed buildings over small regions. At most slight damage to well-designed buildings. 800 per year
6.0-6.9 Strong Can be destructive in areas up to about 160 kilometres (100 mi) across in populated areas. 120 per year
7.0-7.9 Major Can cause serious damage over larger areas. 18 per year
8.0-8.9 Great Can cause serious damage in areas several hundred miles across. 1 per year
9.0-9.9 Devastating in areas several thousand miles across.
1 per 20 years
10.0+ Epic Never recorded; see below for equivalent seismic energy yield.
Extremely rare (Unknown)
(Based on U.S. Geological Survey documents.)[5]
Great earthquakes occur once a year, on average. The largest recorded earthquake was the Great Chilean Earthquake of May 22, 1960 which had a magnitude (MW) of 9.5.[6]
The following table lists the approximate energy equivalents in terms of TNT explosive force[7] - though note that the energy here is that of the underground energy release (i.e. a small atomic bomb blast will not simply cause light shaking of indoor items) rather than the overground energy release; the majority of energy transmission of an earthquake is not transmitted to and through the surface, but is instead dissipated into the crust and other subsurface structures.
Richter
Approximate Magnitude Approximate TNT for
Seismic Energy Yield Joule equivalent Example
0.0 1 kg (2.2 lb) 4.2 MJ
0.5 5.6 kg (12.4 lb) 23.5 MJ Large hand grenade
1.0 32 kg (70 lb) 134.4 MJ Construction site blast
1.5 178 kg (392 lb) 747.6 MJ WWII conventional bombs
2.0 1 metric ton 4.2 GJ Late WWII conventional bombs
2.5 5.6 metric tons 23.5 GJ WWII blockbuster bomb
3.0 32 metric tons 134.4 GJ Massive Ordnance Air Blast bomb
3.5 178 metric tons 747.6 GJ Chernobyl nuclear disaster, 1986
4.0 1 kiloton 4.2 TJ Small atomic bomb
4.5 5.6 kilotons 23.5 TJ
5.0 32 kilotons 134.4 TJ Nagasaki atomic bomb (actual seismic yield was negligible since it detonated in the atmosphere)
Lincolnshire earthquake (UK), 2008
5.4 150 kilotons 625 TJ 2008 Chino Hills earthquake (Los Angeles, United States)
5.5 178 kilotons 747.6 TJ Little Skull Mtn. earthquake (NV, USA), 1992
Alum Rock earthquake (CA, USA), 2007
6.0 1 megaton 4.2 PJ Double Spring Flat earthquake (NV, USA), 1994
6.5 5.6 megatons 23.5 PJ Rhodes (Greece), 2008
Eureka Earthquake (Humboldt County CA, USA), 2010
6.7 16.2 megatons 67.9 PJ Northridge earthquake (CA, USA), 1994
6.9 26.8 megatons 112.2 PJ San Francisco Bay Area earthquake (CA, USA), 1989
7.0 32 megatons 134.4 PJ Java earthquake (Indonesia), 2009
12 January 2010 earthquake (Haiti)
7.1 50 megatons 210 PJ Energy released is equivalent to that of Tsar Bomba, the largest thermonuclear weapon ever tested.
7.5 178 megatons 747.6 PJ Kashmir earthquake (Pakistan), 2005
Antofagasta earthquake (Chile), 2007
7.8 600 megatons 2.4 EJ Tangshan earthquake (China), 1976
8.0 1 gigaton 4.2 EJ Toba eruption[citation needed] 75,000 years ago; the largest known volcanic event
San Francisco earthquake (CA, USA), 1906
Queen Charlotte earthquake (BC, Canada), 1949
México City earthquake (Mexico), 1985
Gujarat earthquake (India), 2001
Chincha Alta earthquake (Peru), 2007
Sichuan earthquake (China), 2008 (initial estimate: 7.8)
8.5 5.6 gigatons 23.5 EJ Sumatra earthquake (Indonesia), 2007
9.0 32 gigatons 134.4 EJ Lisbon Earthquake (Lisbon, Portugal), All Saints Day, 1755
9.1 67 gigatons 477 EJ Indian Ocean earthquake, 2004 (40 ZJ in this case)
9.2 90.7 gigatons 379.7 EJ Anchorage earthquake (AK, USA), 1964
9.5 178 gigatons 747.6 EJ Valdivia earthquake (Chile), 1960 (251 ZJ in this case)
10.0 1 teraton 4.2 ZJ Never recorded by humans.
13.0 108 megatons = 100 teratons 5x1030 ergs = 500 ZJ Yucatán Peninsula impact (causing Chicxulub crater) 65 Ma ago.[8][9][10][11][12]
Less than 2.0 Micro Microearthquakes, not felt. About 8,000 per day
2.0-2.9 Minor Generally not felt, but recorded. About 1,000 per day
3.0-3.9 Often felt, but rarely causes damage. 49,000 per year (est.)
4.0-4.9 Light Noticeable shaking of indoor items, rattling noises. Significant damage unlikely. 6,200 per year (est.)
5.0-5.9 Moderate Can cause major damage to poorly constructed buildings over small regions. At most slight damage to well-designed buildings. 800 per year
6.0-6.9 Strong Can be destructive in areas up to about 160 kilometres (100 mi) across in populated areas. 120 per year
7.0-7.9 Major Can cause serious damage over larger areas. 18 per year
8.0-8.9 Great Can cause serious damage in areas several hundred miles across. 1 per year
9.0-9.9 Devastating in areas several thousand miles across.
1 per 20 years
10.0+ Epic Never recorded; see below for equivalent seismic energy yield.
Extremely rare (Unknown)
(Based on U.S. Geological Survey documents.)[5]
Great earthquakes occur once a year, on average. The largest recorded earthquake was the Great Chilean Earthquake of May 22, 1960 which had a magnitude (MW) of 9.5.[6]
The following table lists the approximate energy equivalents in terms of TNT explosive force[7] - though note that the energy here is that of the underground energy release (i.e. a small atomic bomb blast will not simply cause light shaking of indoor items) rather than the overground energy release; the majority of energy transmission of an earthquake is not transmitted to and through the surface, but is instead dissipated into the crust and other subsurface structures.
Richter
Approximate Magnitude Approximate TNT for
Seismic Energy Yield Joule equivalent Example
0.0 1 kg (2.2 lb) 4.2 MJ
0.5 5.6 kg (12.4 lb) 23.5 MJ Large hand grenade
1.0 32 kg (70 lb) 134.4 MJ Construction site blast
1.5 178 kg (392 lb) 747.6 MJ WWII conventional bombs
2.0 1 metric ton 4.2 GJ Late WWII conventional bombs
2.5 5.6 metric tons 23.5 GJ WWII blockbuster bomb
3.0 32 metric tons 134.4 GJ Massive Ordnance Air Blast bomb
3.5 178 metric tons 747.6 GJ Chernobyl nuclear disaster, 1986
4.0 1 kiloton 4.2 TJ Small atomic bomb
4.5 5.6 kilotons 23.5 TJ
5.0 32 kilotons 134.4 TJ Nagasaki atomic bomb (actual seismic yield was negligible since it detonated in the atmosphere)
Lincolnshire earthquake (UK), 2008
5.4 150 kilotons 625 TJ 2008 Chino Hills earthquake (Los Angeles, United States)
5.5 178 kilotons 747.6 TJ Little Skull Mtn. earthquake (NV, USA), 1992
Alum Rock earthquake (CA, USA), 2007
6.0 1 megaton 4.2 PJ Double Spring Flat earthquake (NV, USA), 1994
6.5 5.6 megatons 23.5 PJ Rhodes (Greece), 2008
Eureka Earthquake (Humboldt County CA, USA), 2010
6.7 16.2 megatons 67.9 PJ Northridge earthquake (CA, USA), 1994
6.9 26.8 megatons 112.2 PJ San Francisco Bay Area earthquake (CA, USA), 1989
7.0 32 megatons 134.4 PJ Java earthquake (Indonesia), 2009
12 January 2010 earthquake (Haiti)
7.1 50 megatons 210 PJ Energy released is equivalent to that of Tsar Bomba, the largest thermonuclear weapon ever tested.
7.5 178 megatons 747.6 PJ Kashmir earthquake (Pakistan), 2005
Antofagasta earthquake (Chile), 2007
7.8 600 megatons 2.4 EJ Tangshan earthquake (China), 1976
8.0 1 gigaton 4.2 EJ Toba eruption[citation needed] 75,000 years ago; the largest known volcanic event
San Francisco earthquake (CA, USA), 1906
Queen Charlotte earthquake (BC, Canada), 1949
México City earthquake (Mexico), 1985
Gujarat earthquake (India), 2001
Chincha Alta earthquake (Peru), 2007
Sichuan earthquake (China), 2008 (initial estimate: 7.8)
8.5 5.6 gigatons 23.5 EJ Sumatra earthquake (Indonesia), 2007
9.0 32 gigatons 134.4 EJ Lisbon Earthquake (Lisbon, Portugal), All Saints Day, 1755
9.1 67 gigatons 477 EJ Indian Ocean earthquake, 2004 (40 ZJ in this case)
9.2 90.7 gigatons 379.7 EJ Anchorage earthquake (AK, USA), 1964
9.5 178 gigatons 747.6 EJ Valdivia earthquake (Chile), 1960 (251 ZJ in this case)
10.0 1 teraton 4.2 ZJ Never recorded by humans.
13.0 108 megatons = 100 teratons 5x1030 ergs = 500 ZJ Yucatán Peninsula impact (causing Chicxulub crater) 65 Ma ago.[8][9][10][11][12]
