Earthquakes

The size of earthquakes is determined by measuring the amplitude of the seismic waves recorded on a seismograph. A formula is applied to these which converts them to a magnitude scale, a measure of the energy released by the earthquake.

For every unit increase in magnitude, there is roughly a thirty-fold increase in the energy released. For instance, a magnitude 2.0 earthquake releases 30 times more energy than a magnitude 1.0 earthquake, while a magnitude 3.0 earthquake releases 900 times (30x30) more energy than a magnitude 1.0.

A magnitude 8.6 earthquake releases energy equivalent to about 10,000 atomic bombs of the type developed in World War II.

The effects of an earthquake depend on many factors, such as the distance from the epicentre and the local ground conditions. Generally, for locations near the epicentre, the following effects may be observed:

Richter Scale	Description	Effects	Frequency
Less than 2.0	Micro	Micro earthquakes, 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	Minor	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 kilometres across.	1 per year
9.0-9.9	Great	Devastating in areas several thousand kilometres across.	1 per 20 years
10.0+	Massive	Never recorded, widespread devastation across very large areas; see below for equivalent seismic energy yield.	Extremely rare (Unknown)

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The 10 Largest Recorded Earthquakes
Mag	Location	Year
9.5	Valdivia, Chile	1960
9.2	Pr. William Sound, Alaska	1964
9.1	Northern Sumatra	2004
9.0	Honshu, Japan	2011
9.0	Kamchatka Peninsula	1952
8.8	Maule, Chile	2010
8.8	Ecuador	1906
8.7	Rat Islands, Alaska	1965
8.6	Sumatra, Indonesia	2005
8.6	Assam, Tibet	1950

Earthequake Report

(Major) Earthquakes list May 18, 2012 - Moderate earthquake shakes the interior of Honshu, Japan

Not dangerous : Iran, Japan (Ryukyu Islands), Chile, Nicaragua, Panama

(Complete) Earthquakes list May 18, 2012

All today's M 2.5+ earthquakes as reported by the major international seismological agencies

Second earthquake in 7 days near Timpson, Texas, USA + I Felt It reports + shaking video

17.05.2012 - After an initial earthquake on May 10 with a Magnitude of 3.9, an even stronger M4.3 aftershock rattled the Timpson, Texas area.

(Complete) Earthquakes list May 17, 2012

All today's M 2.5+ earthquakes as reported by the major international seismological agencies

(Major) Earthquakes list May 17, 2012 - Strong aftershock in Texas

Not dangerous : Indonesia (Nias, Celebes Sea), Venezuela, Philippines, Atlantic Ocean, Chile, USA (Texas), Vanuatu, Iran, Santa Cruz Islands

(Major) Earthquakes list May 16, 2012 - Moderate earthquake close to Anchorage, Alaska

Not dangerous : Tonga, Papua New Guinea, Indonesia (Molucca Sea, Papua, Nias), Chile, Alaska

(Complete) Earthquakes list May 16, 2012

All today's M 2.5+ earthquakes as reported by the major international seismological agencies

(Major) Earthquakes list May 15, 2012

Not dangerous : Indonesia (Molucca Sea, Celebes Sea), Japan (Honshu), Indian Ocean, Peru, Atlantic Ocean, Indian Ocean, Kermadec Islands, Papua New Guinea, Tonga

(Complete) Earthquakes list May 15, 2012

All today's M 2.5+ earthquakes as reported by the major international seismological agencies

(Major) Earthquakes list May 14, 2012 - Strong earthquake in Peru / Chile

Not dangerous : Indonesia (Seram, Molucca Sea), Japan (Kyushu), Fiji, Chile/Peru, Iran, Russia (Siberia)