Geology

Since December 2004 there have been 18 quakes of 8.0 or greater on the moment magnitude (Mw) scale – a rate more than twice that seen from 1900 to mid-2004.

Some of that difference could be due to unprecedented advances in technological and scientific capacity to detect earthquakes. Like the distance of Babe Ruth's homeruns, anecdotes about past earthquakes have the mist of legend shrouding them, but modern earthquakes have a variety of ways they can be understood - and that helps recalibrate risk for future earthquakes.


A study of Samoan volcano hotspots has found evidence of the planet's early formation still trapped inside the Earth.

Volcanic island chains such as Samoa can contain ancient primordial signatures from the early solar system that have survived for billions of years. To make their determination, the researchers utilized high-precision lead and helium isotope measurements to unravel the chemical composition and geometry of the deep mantle plume feeding Samoa's volcanoes. 

In most cases, volcanoes are located at the point where two tectonic plates meet, and are created when those plates collide or diverge. Hotspot volcanoes, however, are not located at plate boundaries but rather represent the anomalous melting in the interior of the plates.


Hydraulic fracturing, commonly called fracking, is a way to extract natural gas from shale rock, by using a modern process to inject a high-pressure water mixture at the rock to release the gas inside. By all accounts it has been an environmental boon, responsible for causing energy emissions from coal to plummet back to early 1980s levels without causing energy prices to rise and harm poor people.


Four urban sections of the San Andreas Fault system in Northern California have stored enough energy to produce major earthquakes, according to a new study of 'fault creep', and three fault sections, near Hayward, Rodgers Creek and Green Valley, are nearing or past their average recurrence interval. 



Phreatic eruption: Mount Ontake. Credit: EPA/Ministry of Land, Infrastructure

By Rebecca Williams, University of Hull

Mount Ontake, Japan’s second-highest volcano, erupted killing at least 31 people on September 27.

Since then, there has been feverish speculation about why tourists were on an active volcano and why the eruption wasn’t predicted.

Planetary geologists have speculated for decades that glaciers might once have crept through Valles Marineris, the 2,000-mile-long chasm that constitutes the Grand Canyon of Mars.

Using satellite images, astronomers have identified features they say might have been carved by past glaciers as they flowed through the canyons but those claims have remained highly controversial and contested. 

Now, a joint team from Bryn Mawr College and the Freie Universitaet Berlin has identified what could be the first mineralogical evidence of past glaciers within the Valles Marineris: a layer of mixed sulfate minerals halfway up the three-mile-high cliffs of Ius Chasma at the western end of the canyon system.

Volcano season. Some think it's the time of the year. Credit: EPA

By Robin Wylie, University College London


Landslides on Mars typically have runout distances much larger than equivalent features on Earth, and therefore can interact with older landforms that are distal to the failure scarp.

Regardless of the exact formation mechanism of these landslides, it is evident that their combined large area and relatively well constrained formation age can be exploited to better understand the evolution of coincident features, particularly if those features have been modified since the landslide event.


Credit: Image of map courtesy of the USGS and composite image by Patricia Waldron

By: Patricia Waldron, Inside Science

(Inside Science) -- People living in Afghanistan have mined precious gems from their land, such as lapis lazuli, since the times of the Egyptian pharaohs. But modern analyses of the country's mineral deposits show that the Afghan people have barely scratched the surface of their mineable wealth.

The 500 million years after Earth formed were not the hot, lava-filled Hell commonly portrayed, it may have had oceans, continents and active crustal plates - a lot like we have today.

This alternate view of Earth's first geologic eon, called the Hadean, gets support from the first detailed comparison of zircon crystals that formed more than 4 billion years ago with those formed contemporaneously in Iceland, which has been proposed as a possible geological analog for early Earth.