If you’ve ever wondered where — and why — earthquakes happen the most, look no further! I found a beautiful and arresting map (by John Nelson), which plots more than a century’s worth (since 1898) of nearly every recorded earthquake of magnitude 4.0 or greater. Each is marked in a lightning-bug hue that glows brighter with increasing magnitude. The overall effect reveals the silhouettes of Earth’s tectonic boundaries in stark, luminous swarms of color. In all, 203,186 earthquakes are marked on the map, which is current through 2003.
Just a perfect map for people to understand and learn about the formation of our planet, plate techtonics, volcanology and Earth geology.Great and wonderful work!
This map explains plate techtonic by 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 the map shows that the real earthquake action is elsewhere, namely at subduction zones (standing out like a Vegas light show on the map), the places where tectonic plates overlap and one is forced to dive deep beneath the other and into the Earth’s crushing interior.
Here a little movie explaining what magnitude is! Interesting! Sorry I could not remove the ad!