Earthquakes

earthquake-predictionGeological Map of the Ocean Floor & Prediction of Powerful Earthquakes

The Poseidon Ensemble:  Earthquake Music (David Johnson)   …   100 years of global earthquake data, as sounds.  (Poseidon was:  “God of the sea and rivers, creator of storms and floods, and the bringer of earthquakes and destruction….”)

Moon’s pull can trigger big earthquakes   …   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.

 

You can see fracking’s impact on Earth’s surface from space   …   Fracking can lift Earth’s surface, a movement that has now been detected from space and can help predict where quakes induced by the activity are likely to strike. 

This slight buckling – just 3 millimetres a year – happened when frackers injected waste water at high pressure into rocks deep underground.

The deformations were seen near the location of the biggest quake ever recorded in eastern Texas: the magnitude 4.8 Timpson earthquake in 2012, widely blamed on waste water being injected at fracking sites close to the eponymous town.   

Shirzaei says earthquakes were almost unheard of in the US Midwest prior to the fracking boom that began around 2008. But between 2009 and 2015, there have been 1570 with magnitudes exceeding 3.

 

Stalagmites in Indiana cave may record past earthquakes   …   Among the four Donnehue stalagmites in the study, the research team found a twin stalagmite pair that had stopped growing around 100,000 years B.P. and then resumed growing at around 6000 years B.P., overlapping in time with a magnitude 7.1 to 7.3 earthquake in the area. Another younger stalagmite began growing around 1800 years B.P.–coinciding with a magnitude 6.2 earthquake–and showed later shifts in its growth axis that overlap with other seismic events in the nearby New Madrid Seismic Zone.

  

Study Finds Earthquakes Can Trigger Near-Instantaneous Aftershocks on Different Faults   …   In one instance along the Sundra arc subduction zone, where the magnitude 9 Sumatra-Andaman mega-earthquake occurred off the coast of Indonesia in 2004, a magnitude 7 quake triggered two large aftershocks over 200 kilometers (124 miles) away.

 

 na-pnw-earthquake-risk

Seabed samples cast doubt on earthquake risk for Pacific Northwest

 

M9 Cascadia Megathrust Earthquake of January 26, 1700   …   At 9PM on January 26, 1700 one of the world’s largest earthquakes occurred along the west coast of North America. The undersea Cascadia thrust fault ruptured along a 1000 km length, from mid Vancouver Island to northern California in a great earthquake, producing tremendous shaking and a huge tsunami that swept across the Pacific. The Cascadia fault is the boundary between two of the Earth’s tectonic plates: the smaller offshore Juan de Fuca plate that is sliding under the much larger North American plate.

  

Seven-year legal saga ends as Italian official is cleared of manslaughter in earthquake trial   …   The trial of Bertolaso follows that of the scientists themselves—three seismologists, a volcanologist, two seismic engineers, and Bertolaso’s deputy….   [Accused of downplaying the risk of an earthquake.]

 

Mystery Rocks of the Cypress Hills (Saskatchewan, Canada)   …   “What pattern of stresses might have caused this pattern of fractures?”  Enter your best guess on the site, and challenge your family and friends to do the same.

 

San Andreas Fault Line Blues (Shovels & Rope)


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