Temperature and shear stress are two influential variables that affect faulting and seismicity in subduction zones, where tectonic plates converge. Yet because earthquakes originate tens of kilometers below Earth's surface at plate boundaries, the effects of temperature and the magnitude of stress are poorly understood and hotly debated.
Philip England and colleagues explored these variables at the plate boundary in northern Honshu, Japan's largest island and the setting of the devastating Tōhoku earthquake in 2011—the most powerful ever recorded in Japan. The authors used a dense set of heat flux measurements collected from 100-meter-deep boreholes as a proxy for measurements at the inaccessible plate interface.
The findings are published in the journal Geochemistry, Geophysics, Geosystems.
A proposal to codify a new geological epoch based on humanity's influence on Earth has been rejected.
It means "the Anthropocene" will not be added to the chronostratigraphic chart featured in textbooks and on classroom posters to record the major changes in Earth history.
The International Union of Geological Sciences upheld an earlier vote by a lower committee to dismiss the idea.
But it also recognised the term "Anthropocene" had common currency.
"Despite its rejection as a formal unit of the geologic timescale, the Anthropocene will nevertheless continue to be used not only by Earth and environmental scientists but also by social scientists, politicians and economists as well as by the public at large," the IUGS said.
