Taxonomy term

fault

Revealing potential tsunami inundation on California coast

Earthquakes are well known along Southern California’s coast, and existing hazard maps indicate where quake-triggered tsunamis could flood the coastline. But in a new modeling study published in Geophysical Research Letters, researchers found that an earthquake-generated tsunami northwest of Los Angeles may reach farther inland than is currently projected.
 
06 Feb 2016

Subducting seamounts blocked a big quake in Chile

Chile, which lies above a massive subduction zone fault, is one of the world’s most earthquake-prone countries, experiencing nine temblors of magnitude 7 or greater since 2010. In April 2014, a magnitude-8.1 earthquake struck 95 kilometers northwest of the city of Iquique, but despite its large size, the event failed to release all the stress thought to have built up along that portion of the fault. A new study reveals that a ridge of ancient underwater volcanoes may have blocked the 2014 earthquake rupture from propagating farther, thus limiting the size of the quake.
 

 

20 Jan 2016

Balanced boulders in earthquake country highlight interconnected faults

Precariously balanced boulders look like bizarre accidents in any landscape, but when they’re found in regions famous for frequent earthquakes, such gravity-defying formations are even more improbable. Scientists have long wondered about an odd collection of dozens of balanced boulders in the San Bernardino Mountains that seemingly should have been toppled centuries ago by the earthquakes that regularly shake Southern California. Even stranger, these car- to house-sized granite boulders are located within 10 kilometers of the active San Andreas and San Jacinto faults. Now, new detective work on 36 of the boulders is giving scientists clues about the connections between these faults. 
 
14 Dec 2015

Down to Earth With: Geophysicist Julian Lozos

Julian Lozos, a postdoctoral researcher affiliated with both the U.S. Geological Survey and Stanford University, designs computer models that simulate earthquakes. As a graduate student at the University of California at Riverside (UC Riverside), Lozos discovered part of what makes the San Jacinto Fault — a major fault in Southern California underlying the homes of millions — tick. For this work, Lozos received the Outstanding Student Presentation award at the annual meeting of the Seismological Society of America three years in a row, an unprecedented accomplishment.
 
29 Oct 2015

Source of Red Sea's mysterious cannon earthquakes revealed

For decades, people living along Egypt’s Red Sea coast have reported hearing loud blasts accompanying the small earthquakes that regularly jolt the Abu Dabbab region. And there is evidence the sounds have been occurring for much longer: Abu Dabbab means “the Father of Knock” in Arabic, hinting at a tectonic mystery at least as ancient as the name of the long-inhabited coastal region. Now, scientists are offering a novel explanation for the uniquely noisy seismic events, and their discovery is revealing new information about the underlying structure of the Red Sea region. 
 
08 Oct 2015

Injection experiment offers new view of fluid-filled faults

Scientists have known since the late 1960s that injecting fluids underground can cause earthquakes if those fluids find their way into slip-prone fault zones. Evidence of fluid-induced quakes has continued mounting in recent years with observations of abnormally high levels of seismicity in the central U.S., coincident with increased injections of wastewater into the ground — mostly related to oil- and gas-mining operations. But understanding the inner workings of fluid-filled faults is challenging because researchers have been limited by how close they can get to study them. Now, a new study is offering a glimpse into the future of induced-seismicity studies by monitoring fault motions on the spot and in real time.
 
19 Sep 2015

A decade of slow slip may have preceded Japan's 2011 earthquake

Everyone notices when a fault ruptures quickly — the ground shakes and shudders, and sometimes, the seas churn. However, tectonic plates can also creep past each other so slowly that it’s almost imperceptible. Researchers say they’ve now identified the longest example to date of this type of movement along the Japan Trench in the decade leading up to the devastating magnitude-9.0 earthquake that shook the island of Honshu in 2011.

12 May 2015

Small tremor could have triggered big Chilean quake

On April 1, 2014, a magnitude-8.2 earthquake shook the empty stretch of coast where Chile arcs into Peru, a region called the Iquique Gap. The gap is the only part of the 7,000 kilometer-long boundary between the Nazca and South American plates that hadn’t ruptured in the past century, despite a collision rate of almost 65 millimeters per year.

 
11 Apr 2015

Seismic friction causes fault iridescence

Although iridescent spots on rocks in Utah’s Wasatch Fault Zone were first recognized two decades ago, scientists haven’t understood their origin, until now. New research shows that the iridescence appears on fault surfaces subjected to flash heating from friction and that the spots can provide clues to ancient seismic events. 

11 Nov 2014

In Turkey, the older the fault, the bigger the quake: Good news for Istanbul?

For decades, Istanbul has been bracing for a major earthquake from the dangerously active North Anatolian Fault, which passes just 20 kilometers south of Turkey’s largest city. A new study looking at the age of the fault zone may set a cap on the maximum quake size that could hit Istanbul, suggesting that the older, more mature sections of the zone in the east are capable of bigger earthquakes than the younger sections in the west, which are near the city.
 

05 Sep 2014

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