seismology

From an earthquake perspective, 2011 was a remarkable year. While the devastation accompanying the magnitude-9.0 Tohoku earthquake that occurred off the coast of Japan on March 11 still captures attention worldwide, the relatively stable interior of the U.S. was struck by a somewhat surprising number of small-to-moderate earthquakes that were widely felt. Most of these were natural events, the types of earthquakes that occur from time to time in all intraplate regions.

In Italy, seismologists who failed to predict the L’Aquila earthquake in 2009 could face manslaughter charges.

This year is the 200th anniversary of the New Madrid quakes, the series of magnitude-7 to -8 earthquakes that rocked parts of Missouri and Arkansas in the winter of 1811-1812. But even 200 years later, the quakes continue to shake things up. And the Federal Emergency Management Agency (FEMA) is taking precautions — or maybe not.

During the winter of 1811-1812, three strong earthquakes between magnitude 7 and 8 rocked the New Madrid seismic zone, which runs through parts of eastern Missouri and northeastern Arkansas. The quakes opened deep fissures, destroyed forests and lakes, and produced intense ground shaking that liquefied the soil, turning the land to the consistency of jelly across an area of 10,000 square kilometers.

Updated on Oct. 28, 2010:

The death toll has continued to rise from the natural disasters that struck Indonesia Monday and Tuesday. Currently, officials are reporting 343 people dead with 338 still missing from the earthquake and tsunami. Meanwhile, the eruption of Mount Merapi has killed 33 so far; after a brief lull, the eruption began again on Thursday.

News out of Italy suggests that seven researchers who did not predict the L’Aquila earthquake in April 2009 are under formal investigation and may be charged with gross negligent manslaughter.

A saltwater disposal well, a part of the natural gas production process, may have been responsible for triggering a series of minor earthquakes in the Dallas-Fort Worth area of Texas in 2008, according to a recent study.

Between 1969 and 1972, five Apollo missions installed seismic stations at their landing sites on the nearside of the moon. Because the moon was thought to be seismically dead, the instruments were left almost as an afterthought to detect meteor strikes. But from the time the stations were switched on until they were decommissioned in 1977, they recorded hundreds of internally generated moonquakes, some as strong as magnitude 5.5 on the Richter scale.

A magnitude-7.3 earthquake in Siberia Monday was mistaken by U.S. seismometers as temblors in Idaho and California.

The actual quake occurred about 500 kilometers deep, in the Sea of Okhotsk about 315 kilometers northwest of Russia’s Kamchatka Peninsula, the U.S. Geological Survey reported.

Earthquakes strike out of nowhere — one minute everything is perfectly calm, and the next minute, the ground shakes violently and buildings crumple. However, many seemingly sudden seismic events are actually preceded by a multitude of creeping changes underground. Detecting and interpreting these changes would help forecast earthquakes, but that detection has proven difficult, partly because scientists don’t yet fully understand the complex chain of events that precipitates a quake.

The eyewitness accounts, written in columns from right to left, top to bottom, testify that there was no warning of the tsunami, no shaking to drive villagers to high ground before the wave hit, drowning rice paddies and swamping a castle moat. The entries, written by merchants, peasants and samurai, all clearly mark the time and date: just after midnight on Wednesday, Jan. 27, 1700.

Last June, EARTH reported that seven Italian scientists were under investigation and might be charged with manslaughter for not predicting (and warning the public about) the magnitude-6.3 earthquake that struck L’Aquila, Italy, in April 2009. By last fall, it looked like the charges might be dropped – with the support of many of the world’s seismologists.

On March 11, 2011, at 2:46 p.m. local time, a magnitude-9.0 earthquake ruptured a 500-kilometer-long fault zone off the northeast coast of Japan. Its epicenter was 130 kilometers off Sendai, Honshu; it occurred at a relatively shallow depth of 32 kilometers. The temblor violently shook northeast Honshu for six minutes, and collapsed its coastline by one meter.

In the aftermath of the devastating magnitude-9.0 earthquake and tsunami that struck the Tohoku region of Japan on March 11, attention quickly turned away from a much smaller, but also highly destructive earthquake that struck the city of Christchurch, New Zealand, just a few weeks earlier, on Feb. 22.

A powerful magnitude-8.9 earthquake struck near the eastern coast of Honshu, Japan, today at 2:46 p.m. local time. The quake sent a tsunami racing across the Pacific Ocean to Hawaii, making landfall just before 3 a.m. local time. The Pacific Tsunami Warning Center has more information.