News by Subject Earth Science

Researchers at ETH Zurich working together with an international team have been able to use seismic data to look inside Mars for the first time. They measured the crust, mantle and core and narrowed down their composition. The three resulting articles are being published together as a cover story in the journal Science.

The plates of the Earth's crust perform complicated movements that can be attributed to quite simple mechanisms. That is the short version of the explanation of a rift that began to tear the world apart over a length of several thousand kilometers 105 million years ago. The scientific explanation appears in Nature Geoscience.

Seismic waves passing through the ground near Longyearbyen in the Adventdalen valley, Svalbard, Norway have been slowing down steadily over the past three years, most likely due to permafrost warming in the Arctic valley.

As tectonic plates slip past each other, the rivers that cross fault lines change shape. The shifting ground stretches the river channels until the water breaks its course and flows onto new paths. In a study published July 9 in Science, researchers at UC Santa Cruz created a model that helps predict this process. It provides broad context to how rivers and faults interact to shape the nearby topography.

The Hikurangi Margin, located off the east coast of the North Island of New Zealand, is partly responsible for the more than 15,000 earthquakes the region experiences each year. Most are too small to be noticed, but between 150 and 200 are large enough to be felt. Scientists have been working to understand why this plate boundary produces both imperceptible silent earthquakes, but also potentially major ones. A study published today in the journal Nature offers new perspective and possible answers.

Slow earthquakes are long-period earthquakes that are not so dangerous alone, but are able to trigger more destructive earthquakes. Their origins lie in tectonic plate boundaries where one plate subsides below another. Though the causal mechanism is already known, there has been a lack of data to accurately model the life cycle of slow earthquakes. For the first time, researchers use deep-sea boreholes to gauge pressures far below the seafloor.

New analysis of Venus' surface shows evidence of tectonic motion in the form of crustal blocks that have jostled against each other like broken chunks of pack ice. Published in the PNAS, the study -- which includes contributions by Baylor University planetary physicist Peter James, Ph.D. -- found that the movement of these blocks could indicate that Venus is still geologically active and give scientists insight into both exoplanet tectonics and the earliest tectonic activity on Earth.