Geodynamics

Imaggeo on Mondays: Isolated atoll

Laura Roberts-Artal September 25, 2017

Isolated . Credit: Fulvia Favaro (distributed via imaggeo.egu.eu)

Covering a total area of 298 km², the idylic natural atolls and reefs of the Maldives stretch across the Indian Ocean. The tropical nation is famous for it’s crystal clear waters and picture perfect white sand beaches, but how did the 26 ring-shaped atolls and over 1000 coral islands form? Coral reefs commonly form immediately around an island, creating a fringe which projects seawards from the sh ...[Read More]

GeoTalk: The anomaly in the Earth’s magnetic field which has geophysicists abuzz

Laura Roberts-Artal September 21, 2017

The South Atlantic Anomaly (SAA, the large red area in the image) is a dip in the Earth's magnetic field which allows cosmic rays, and charged particles to reach lower into the atmosphere. This interferes with communication with satellites, aircraft, and the Space Shuttle. While there are theories as to why this occurs, the geologic origin is not yet known. The data were collected by the South Atlantic Anomaly Detector (SAAD) aboard ROSAT. It consists of 10 cm² of Germanium and served as a particle background monitor. The SAAD was used to "safe" the PSPC if rates became too high. Source: ROSAT SAA Guest Observer Facility (NASA Goddard Space Flight Centre) . Credit: S. L. Snowden

Geotalk is a regular feature highlighting early career researchers and their work. In this interview we speak to Jay Shah, a PhD student at Imperial College London, who is investigating the South Atlantic Anomaly, a patch over the South Atlantic where the Earth’s magnetic field is weaker than elsewhere on the globe. He presented some of his recent findings at the 2017 General Assembly. First, coul ...[Read More]

Mexico earthquakes: What we know so far

Laura Roberts-Artal September 20, 2017

USGS interactive map of M 7.1 earthquake .

On Friday 8 September 2017 at 04:49 am UTC, a magnitude 8.1 earthquake hit off the coast of Mexico, 87 km SW of Pijijiapan. According to the U.S. Geological Survey, the epicentre was at 15.07 N, 93.72 W at a depth of about 69.7 km. Yesterday, another strong (magnitude 7.1) earthquake hit central Mexico, 55 km SSW of the city of Puebla and 120 km south of Mexico City. Despite the lower magnitude, y ...[Read More]

Mapping Ancient Oceans

Grace Shephard September 14, 2017

An example of a new map identifying potential chunks of ancient oceans now located deep inside Earth. A vote map at 1400 km depth has been projected to the surface, and is overlain with the position of the continents (grey-white) at around 120 Million years ago. Credit: G Shephard (CEED/UiO) using GPlates software.

This guest post is by Dr Grace Shephard, a postdoctoral researcher in tectonics and geodynamics at the Centre of Earth Evolution and Dynamics (CEED) at the University of Oslo, Norway. This blog entry describes the latest findings of a study that maps deep remnants of past oceans. Her open access study, in collaboration with colleagues at CEED and the University of Oxford, was published this week i ...[Read More]