Taxonomy term

fault

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

Are slow-slip earthquakes under Tokyo stressing faults?

More than 13 million people live in Tokyo, a city that has been devastated by earthquakes in the past and is likely to be rocked again. Since the massive magnitude-9 Tohoku earthquake and tsunami in March 2011, recurrence intervals for nondamaging slow-slip quakes beneath Japan's capital have shortened. And that has left seismologists to wonder if this aseismic creep could be signaling a countdown to Tokyo's next "big one."

07 Aug 2014

Sudden gas eruption shakes the ground near Rome's airport

On Aug. 24, 2013, visitors arriving at Rome’s Leonardo da Vinci International Airport, located in the Fiumicino municipality, flew over a surprising hazard: a gas emission that suddenly exploded from the ground a few meters outside the airport compound. The expulsion, referred to as the Fiumicino Gas Vent (FGV), occurred about 15 kilometers southwest of Rome and was first noticed by passing motorists. Shortly after the explosion, scientists sought  to determine the gas’ makeup and whether it posed a continuing danger.

03 Mar 2014

Big quakes topple traditional views of fault behavior

If rules are made to be broken, then perhaps conventional wisdom is made to be overturned. The spate of large earthquakes in recent years — the magnitude and location of which have defied scientific expectations in several cases — has provided ample support for these maxims, at least within earth science. For all the confusion, though, data emerging from these events are reshaping and improving our understanding of how faults operate.

14 Apr 2013

Well-healed faults produce high-frequency earthquake waves

Much like our voices create sound waves with a variety of low and high pitches, or frequencies, earthquakes also produce seismic waves over a spectrum of frequencies. The seismic waves’ frequencies determine, in part, how far they travel and how damaging they are to human-made structures. But teasing out the details of how quake-generating faults influence seismic frequencies is no easy task, mainly because faults tend to be buried deep underground.

10 Mar 2013

Benchmarks: May 15, 1909: The Northern Great Plains earthquake

In Culbertson, Mont., at a quarter past nine on a Saturday evening, Ralph Bush and H.G. Walsh were resting in the third-floor apartment of the Reed Cash Grocery when the floor began to rock, vibrating a small penknife right off their table, and sending a candle lamp clattering to the floor. At the nearby Evans Hotel, confusion reigned as the quake shook the two-story brick building, causing frightened guests to flee into the streets. On the second story of the Farmers & Merchants bank, a piano player was entertaining a social gathering at the home of Professor Dale when the shaking sent a vase crashing to the floor. The 15 seconds of quivering was so pronounced at Skelley’s barbershop that, “It rang up a 50-cent cash sale on the cash register, and it has been keeping me guessing how I can balance the darned thing,” Skelley told a reporter from the Culbertson Republican.
 
02 May 2012

Pages