Physics, Earthquakes
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Stunning Map Reveals World's Earthquakes Since 1898

Stunning Map Reveals World's Earthquakes Since 1898 | Physics, Earthquakes |

If you've ever wondered where — and why — earthquakes happen the most, look no further than a new map, which plots more than a century's worth of nearly every recorded earthquake strong enough to at least rattle the bookshelves.


The map shows earthquakes of magnitude 4.0 or greater since 1898; each is marked in a lightning-bug hue that glows brighter with increasing magnitude.


The overall effect is both beautiful and arresting, revealing the silhouettes of Earth's tectonic boundaries in stark, luminous swarms of color. 


The map's maker, John Nelson, the user experience and mapping manager for IDV Solutions, a data visualization company, said the project offered several surprises.


"First, I was surprised by the sheer amount of earthquakes that have been recorded," Nelson told OurAmazingPlanet. "It's almost like you could walk from Seattle to Wellington [New Zealand] if these things were floating in the ocean, and I wouldn't have expected that."


In all, 203,186 earthquakes are marked on the map, which is current through 2003. And it reveals the story of plate tectonics itself.


The long volcanic seams where Earth's crust is born appear as faint, snaking lines cutting through the world's oceans. The earthquakes along these so-called spreading centers tend to be rather mild. The best studied spreading center, called the Mid-Atlantic Ridge, bisects the Atlantic Ocean, on the right side of the image.


Its Pacific counterpart wanders along the eastern edge of the Pacific Ocean, cutting a wide swath offshore of South America. Another spreading center makes a jog though the Indian Ocean and up through the Red Sea.

But one glance at the map shows that the real earthquake action is elsewhere. Subduction zones, the places where tectonic plates overlap and one is forced to dive deep beneath the other and into the Earth's crushing interior — a process that generates the biggest earthquakes on the planet — stand out like a Vegas light show.


Nelson said this concept hit home particularly for the Ring of Fire, the vast line of subduction zones around the northern and western edge of the Pacific Ocean.


"I have a general sense of where it is, and a notion of plate tectonics, but when I first pulled the data in and started painting it in geographically, it was magnificent," Nelson said. "I was awestruck at how rigid those bands of earthquake activity really are."

Via Dr. Stefan Gruenwald
Ari Meier's curator insight, September 9, 2013 3:34 PM

This is amazing.

Rescooped by Ricardo Reyes from Digital Media Literacy + Cyber Arts + Performance Centers Connected to Fiber Networks!

Earthquakes, tsunamis and volcanoes › Ask an Expert | ABC Science

Earthquakes, tsunamis and volcanoes › Ask an Expert | ABC Science | Physics, Earthquakes |

Causes of quakes

Is it possible for anything living to cause an earthquake?
— Megan


Yes, people can cause an earthquake through human activity. The most common way is by building a dam. It's very common to get small earthquakes after filling a dam, firstly because of the extra load due to the weight of the water; and then secondly because water seeping down into faults can cause them to move if they're at breaking point. Liquid acts as a lubricant enabling faults to slide more easily.


Another way humans can cause earthquakes is with mining - taking material out of the ground also causes little stresses which can results in earthquakes.


Pumping oil out can cause earthquakes by changing the stresses underground or because water pumped down to flush the oil out can have a lubricating effect.


Another human-related cause of earthquakes is when water is pumped through hot rocks several kilometres underground in order to harness geothermal energy. This can cause little tremors, up to magnitude 3 on the Richter Scale. Scientists use these small earthquakes to trace what is happening underground - they can follow exactly where the water is by following the little earthquakes.


— Clive Colins, seismologist, Geoscience Australia


Click headline to read more Ask the Expert Q & As--

Via Chuck Sherwood, Senior Associate, TeleDimensions, Inc
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