Building mountains

Featured image: Yushan (Jade Mountain) in Taiwan. From Wikimedia Commons by Kailing3 under a CC-BY-SA 3.0 license.

Paper: Coseismic Uplift of the 1999 Mw7.6 Chi‐Chi Earthquake and Implication to Topographic Change in Frontal Mountain Belts

Authors: R.Y. Chuang, C.H. Lu, C.J. Yang, Y.S. Lin, and T.Y. Lee

Journal: Geophysical Research Letters

The height of a mountain range results from a hard-fought battle between tectonic plates and the forces of erosion. Earthquakes generated by clashes between plates cause the upward motion of rock even as they shake the landscape, causing large and numerous landslides. When a large earthquake occurs, which process wins? Does more rock go up than come down, leading to a higher mountain range? Or does shaking-induced erosion remove more material than is uplifted by the earthquake? New research suggests that earthquakes might be able to build mountains up faster than landslides can bring them down.

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The strange case of the Kansas earthquake

Featured image: Karst rocks in Segovia, Spain. Photo by Luis Fernández García, CC-BY-SA 2.1.

Paper: Injection-induced earthquakes near Milan, Kansas controlled by karstic networks
Authors: Charlène Joubert, Reza Sohrabi, Justin L. Rubinstein, Gunnar Jansen, Stephen A. Miller

On November 12th, 2014, a magnitude 4.9 earthquake rattled the city of Milan, Kansas. This event was the largest earthquake ever recorded in Kansas, adding to a trend of increasing seismic activity in the state since 2012. What could cause this kind of tectonic excitement in the stable central US?

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Marsquakes give scientists an InSight to Mars

Featured image: An artist’s concept of NASA’s InSight lander on Mars with a cutaway of the surface below. Credit: IPGP/Nicolas Sarter.

Paper: Constraints on the shallow elastic and anelastic structure of Mars from InSight seismic data

Authors: Philippe Lognonné et al.,

Scientists are able to ‘see’ the internal structure of the Earth based on seismic waves recorded during Earthquakes. Earthquakes send seismic waves out in all directions with two main types: (1) surface waves are the major culprits of Earthquake damage as they remain on the surface; (2) faster body waves can travel down within Earth’s interior. The body waves are the fastest seismic waves, consisting of the first (primary; P-wave) and second (secondary, S-wave) waves to arrive at a location away from the epicentre of an Earthquake.

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Tiny wobbles foreshadow big earthquakes

Featured image: A GPS station in the Sawtooth National Forest near Ketchum, Idaho. Photo by Scott Haefner (USGS).

Paper: Months-long thousand-kilometre-scale wobbling before great subduction earthquakes
Authors: J. R. Bedford, M. Moreno, Z. Deng, O. Oncken, B. Schurr, T. John, J. C. Báez, M. Bevis

We’re always on the lookout for earthquake precursors, indicators that the Earth might be gearing up for some shaking, and geophysicists think they might have found a new one: a small but measurable back-and-forth “wobble” of the land starting several months before very big earthquakes hit.

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How to locate oceanic earthquakes without getting your feet wet

Photo of a fence offset by fault slip on the San Andreas during the 1906 San Francisco earthquake

Featured image: A fence broken by the 1906 San Francisco earthquake, by G. K. Gilbert. Public domain.

For the millions of people living near the San Andreas fault zone in California, the billion-dollar question is when the next “big one” is going to happen.

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What Caused the Flood that (Possibly) Gave Rise to an Empire?

Featured image: The Yellow River Breaches its Course by Ma Yuan, Public Domain

Paper: Uranium isotopic constraints on the nature of the prehistoric flood at the Lajia site, China
Authors: Le Li, Jun Chen, David William Hedding, Yuanhe Fu, Maolin Ye, Gaojun Li

A small sand deposit might hold the key to dating the rise of China’s first dynasty. Continue reading “What Caused the Flood that (Possibly) Gave Rise to an Empire?”