Taxonomy term

fault

Water weight and surface rebound trigger small quakes in California

On average, a cubic meter of snow weighs less than 100 kilograms, but heavy, compacted snow can weigh more than 500 kilograms per cubic meter, with glacial ice approaching 900 kilograms per cubic meter. In California, as elsewhere, the weight of winter snow and spring runoff pushes down on the landscape, affecting stresses on fault systems, which may trigger small quakes. As the snow melts and the runoff makes its way downstream, land rebounds, setting off more small earthquakes.

12 Oct 2017

Dehydrated sediment layer made Sumatra quake stronger

Subduction zones are notorious for unleashing great earthquakes and tsunamis, such as the 2004 magnitude-9.1 Sumatra quake that caused shaking and inundations that killed more than 250,000 people and left millions more homeless. However, despite the dangerous reputations of subduction zones, their hazards are still often underestimated. New research reveals how sediments in the Sumatra Trench may have contributed to producing an even bigger earthquake and tsunami than hazard forecasts had estimated.

07 Sep 2017

Stock traders' algorithm finds slow earthquakes

Traders in financial markets use a variety of computer algorithms to help them decide when to buy or sell different stocks. Geologists have now adapted one of these algorithms to improve detection of subtle slow-slip events along faults, paving the way for a better understanding of regional seismic hazards.

02 Aug 2017

Travels in Geology: Geo-diversity and geologic history in the North West Highlands of Scotland

The complex rocks of the North West Highlands of Scotland —which span two-thirds of Earth’s history — include the oldest rocks in the United Kingdom, as well as some young, glacially sculpted landscapes. They also hold a prominent place in the history of geology.
09 May 2017

Kaikoura quake jumped from fault to fault in New Zealand

A magnitude-7.8 earthquake struck New Zealand’s South Island at about midnight on Nov. 14, 2016, causing two fatalities, triggering a tsunami and multiple landslides, and destroying infrastructure across the region. Known as the Kaikoura earthquake, it is the largest quake to hit New Zealand since 2009, and it appears that the rupture jumped from one fault to another multiple times as it propagated. The event is still being investigated, but at the time EARTH went to press, at least 10 faults are reportedly thought to have been involved.

06 Mar 2017

Mercury's recent tectonics revealed

Not so long ago, Mercury was the least-studied planet in the inner solar system, known only from Earth-based observations and from Mariner 10’s brief flyby in the 1970s. In 2011, the MESSENGER spacecraft began orbiting Mercury, imaging the planet’s crater- and fault-scarred surface before crashing into it, as planned, in 2015. As MESSENGER spiraled downward, it took a last series of high-resolution images, analyses of which are revealing new information about the planet’s surface geology, including evidence for recent tectonic activity.

05 Jan 2017

Scientists find earthquakes trigger instantaneous aftershocks on neighboring faults

Earthquake aftershocks may be more unpredictable than previously thought. Researchers studying past quakes say they have identified a new class of aftershocks that can occur within seconds to minutes after the mainshock on neighboring faults.

29 Dec 2016

Lack of afterslip in Nepal hints at mounting tensions

On April 25, 2015, a magnitude-7.8 earthquake struck Nepal, northwest of Kathmandu, damaging much of the capital city, flattening surrounding villages and killing more than 8,000 people. The quake’s hypocenter was relatively shallow, only 15 kilometers below ground on a fault that’s part of the Main Himalayan Thrust. Yet the displacement didn’t rupture all the way to the surface, indicating that only part of the fault slipped. Now, in a new study looking at how the fault continued to move following the 2015 event, researchers have found that the shallower section of the fault is likely still locked — and potentially loaded for another earthquake.

02 Oct 2016

Modeling Io’s weird mountains

Jupiter’s innermost moon, Io, is home to some of the strangest mountains in our solar system: towering isolated peaks, some more than 8,000 meters tall, that jut from the moon’s surface with little evidence of underlying tectonics. Now, a new model may explain how Io’s odd peaks formed.

30 Aug 2016

Earthquakes can jump long distances

Earthquakes are known to “jump” from one fault to another, with the ground ­shaking from one rupture triggering movement on nearby faults. However, evidence for earthquake transference between faults separated by more than a few kilometers has been scarce. Now, researchers looking at two closely timed earthquakes that struck Pakistan in 1997 suggest that earthquakes can jump between faults more than 50 kilometers apart, a finding that may have implications for hazard projections in Southern California and elsewhere.

04 Jul 2016

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