From Princeton- “Frontier beneath our feet: Seismic study aims to map Earth’s interior in 3-D”


Princeton University
Princeton University

March 12, 2015
Catherine Zandonella, Office of the Dean for Research

Computer simulations use the speed of seismic waves from earthquakes to reveal the existence of subterranean structures. In this view of the mantle below the Pacific Ocean, slower waves are shown in red and orange while faster waves are shown in green and blue. The faster waves are associated with subduction zones where one tectonic plate sinks underneath another plate. (Image courtesy of Ebru Bozdağ, University of Nice Sophia Antipolis, and David Pugmire, Oak Ridge National Laboratory)

When a 7.9-magnitude earthquake struck central China’s Sichuan province in 2008, seismic waves rippled through the region, toppling apartment houses in the city of Chengdu and swaying office buildings 1,000 miles away in Shanghai.

Though destructive, earthquakes provide benefit in one respect: they help researchers learn about the structure of the Earth, which in turn could lead to more accurate…

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Casati: new study, major geophysical events and Ap index 1844 onwards

Tallbloke's Talkshop

Dr Michele Casati is familiar to many Talkshop readers as an occassional contributor and for his blog.

A new study is being presented at EGU General Assembly 2015, held 12April – 15April, 2015 in Vienna, Austria

Relationship between major geophysical events and the planetary magnetic Ap index, from 1844 to the present

Michele,Casati; Valentino,Straser


In this study, for the first time, we compared the annual magnetic Ap index, taken from original sources, from 1844 to the present day [Svalgaard,2014], with:

i) sixteen large volcanic eruptions of index VEI5 + recorded by, Smithsonian Institute (Global Volcanism Program), ii) three sets of the volcanic aerosols data [Ammann,2003][Gao;Chaochao;Alan Robock;Caspar Ammann, 2008][Traufetter,2004] and iii) eight major earthquakes of a magnitude between 8.7<M<9.5, which occurred from 1900 to the present.

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