Blog Posts Tagged "tectonics"

50 Years Ago Today in Geology...

Fifty years ago the world looked very different to geologists. Not only was most television still in black and white, but the Grand Unifying Theory of Plate Tectonics had not yet been unified.

Incoming! Oblique Subduction at the Sunda Subduction Zone

The Indian and Australian Plates plow northeast into the Sumatra subduction zone, part of the larger Sunda subduction zone, at a speed of 45 mm/yr. The angle between the direction these two plates move relative to each other is not always at a right angle (90°) to the subduction zone itself--here it is about 50°. Sliding under the Sunda Plate at an angle is not easy, so several large strike-slip fault systems help to accommodate some of this movement. If you thought learning vectors in high school was pointless—think again. This is a perfect vector component problem!

Not So Fast! Types of earthquakes at the Sumatra Seismogenic Zone

Several different types of earthquakes and fault-slip events happen at the Sunda subduction zone and other subduction zones around the world. Typical earthquakes usually last a few seconds to a few minutes, if they have very large magnitude. But not all fault slip results in typical earthquakes.