Tag Archives: earthquakes

Statistical analysis suggests Moon can cause quakes

The uncertainty of science: A careful statistical analysis of when major earthquakes occur has suggested they are more likely to be more powerful if they occur around the full and new moons when tidal forces are at their peak.

Satoshi Ide, a seismologist at the University of Tokyo, and his colleagues investigated three separate earthquake records covering Japan, California and the entire globe. For the 15 days leading up to each quake, the scientists assigned a number representing the relative tidal stress on that day, with 15 representing the highest. They found that large quakes such as those that hit Chile and Tohoku-Oki occurred near the time of maximum tidal strain — or during new and full moons when the Sun, Moon and Earth align.

For more than 10,000 earthquakes of around magnitude 5.5, the researchers found, an earthquake that began during a time of high tidal stress was more likely to grow to magnitude 8 or above.

As these results are based entirely on statistical evidence, not on any direct link between tidal forces and actual quakes, they are quite uncertain and unproven.

Italian appeals court overturns convictions of earthquake scientists

An Italian appeals court on Monday overturned the manslaughter convictions of six Italian earthquake scientist for the deaths of over 300 people during the L’Aquila earthquake of 2009.

Only one of the seven experts originally found guilty was convicted today: Bernardo De Bernardinis, who in 2009 was deputy head of Italy’s Civil Protection Department and who will now serve 2 years in jail, pending any further appeals.

De Bernardinis had been the guy who had publicly said that the swarm of tremors prior to the quake had released energy and thus reduced the chance of an earthquake, a claim that geology scientists do not support.

Scientists struggle with earthquake data in the Pacific northwest

The uncertainty of science: A second look at cores drilled in the Pacific northwest has raised doubts about the previous conclusions that the region faces the threat of megaquakes every few centuries.

The bottom line is that though geologists are very confident the northwest faces the threat of future quakes, they can’t yet predict with any confidence their rate or intensity.

Geologists have determined that the magma reservoir under Yellowstone is much bigger than previously thought.

The uncertainty of science: Geologists have determined that the magma reservoir under Yellowstone is much bigger than previously thought.

Jamie Farrell, a postdoctoral researcher at the University of Utah, mapped the underlying magma reservoir by analysing data from more than 4,500 earthquakes. Seismic waves travel more slowly through molten rock than through solid rock, and seismometers can detect those changes.

The images show that the reservoir resembles a 4,000-cubic-kilometre underground sponge, with 6–8% of it filled with molten rock. It underlies most of the Yellowstone caldera and extends a little beyond it to the northeast.

The geologists also noted that the threat from a huge volcanic eruption is less of a concern than that of earthquakes.

The trial of seven earthquake scientists in Italy on charges of manslaughter for not correctly predicting the earthquake in L’Aquila continued yesterday with each of the defendants testifying.

The trial of seven earthquake scientists in Italy on charges of manslaughter for not correctly predicting the earthquake in L’Aquila continued yesterday with each of the defendants testifying.

The trial will not resume again until the fall.

A big sideways slip on Mars

Mars Reconnaissance Orbiter today released an image of a really spectacular transform fault on Mars, a spot where the ground cracked and two sections moved sideways to each other. In this case, the sideways movement was about 300 feet. The image is posted below the fold.

Compare that with the Japanese magnitude 9 earthquake on March 11, which only shifted the seabed sideways 165 feet while raising it 33 feet. The quake that moved these two pieces of Martian bedrock sideways must have been quite a ride.
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The trial of seven Italian earthquake experts facing manslaughter charges for not correctly predicting an earthquake continued this week.

The trial of seven Italian earthquake experts facing manslaughter charges for not correctly predicting a deadly earthquake continued this week.

The prosecution’s argument that the experts had underplayed the possible occurrence of a major quake was bolstered by testimony from Daniela Stati, the former civil protection officer for Abruzzo, who took an active role in the March 31 meeting. Stati confirmed what she had previously told prosecutors in 2010, that one of the indicted said during the meeting that the continuing tremors represented a “favorable signal” because there was a continuous discharge of energy that made stronger tremors less likely. In fact, scientific evidence suggests that groups of small earthquakes tend instead to increase the chances of a major earthquake nearby, even though the absolute probability of such a quake remains low. Stati said that nobody within the commission objected to this statement. She also underlined that the “reassuring message” given to the press by her, L’Aquila Mayor Massimo Cialente, and two of the indicted, Franco Barberi and Bernardo De Bernardinis, was based on comments made at the meeting.

The strange rubbing boulders of Chile

The strange rubbing boulders of Chile.

Then, on another trip to the Atacama, Quade was standing on one of these boulders, pondering their histories when a 5.3 magnitude earthquake struck. The whole landscape started moving and the sound of the grinding of rocks was loud and clear.

“It was this tremendous sound, like the chattering of thousands of little hammers,” Quade said. He’d probably have made a lot more observations about the minute-long event, except he was a bit preoccupied by the boulder he was standing on, which he had to ride like a surfboard. “The one I was on rolled like a top and bounced off another boulder. I was afraid I would fall off and get crushed.”

The abstract is here.