Sentences with word «mainshock»

When Andrew Barbour of the U.S. Geological Survey and colleagues examined new injection data from nearby disposal wells in Osage County, they found a significant increase in injection rates in the years leading up to the Pawnee mainshock.

Libo Han from the China Earthquake Administration and colleagues provide a preliminary analysis of the Lushan mainshock and two large aftershocks, which appear to have occurred in the upper crust and terminated at a depth of approximately 8 km.

Historically, multiple triggered mainshocks, with time delays of seconds to days, have caused deadly earthquakes along the Italian Apennine belt, a series of central mountain ranges extending the length of Italy.

«Two consecutive mainshocks of magnitude 5.8 could have the effect of a magnitude 6 earthquake in terms of energy release.

Although the Lushan earthquake's mainshock did not break to the surface, the strong shaking still caused significant damage and casualties in the epicentral region.

A close study of the Haida Gwaii mainshock by Kao et al. revealed the Pacific plate slid at a low angle below the North American plate on a previously suspected thrust fault, confirming the presence of subduction activity in the area.

The 2012 Emilia sequence started with an M 5.9 event, with the second largest mainshock (M 5.8) occurring nine days later, and included more than 2000 aftershocks.

«Although the simulated earthquake - induced tsunamis are not small, there has been a recorded history of significantly larger events, in terms of earthquake magnitude and mainshock areas, taking place in the region,» says Samaras.

Clusters of earthquakes happen in the Apennines all the time without leading to anything bigger, and the 3 - day mainshock probabilities following the March 30th cluster were less than 1 percent, representing an increase, but still very low.

Fluid levels rose with the Pawnee quake and lowered slightly with the Cushing quake, indicating that the Pawnee earthquake especially altered the fluid flow through regional rock layers up to 50 kilometers from the Pawnee mainshock.

Seismicity patterns after large earthquakes suggest that the earthquake hazard can rise sharply in areas well beyond the mainshock rupture zone.

Scientists generally believe that most aftershocks are triggered by stress changes caused by the permanent movement of the fault during the main seismic event, and mainly occur near the mainshock rupture where these stress changes are largest.

In the study, published in the Sept. 9 issue of the journal Science, Scripps geophysicist Peter Shearer and Scripps graduate student Wenyuan Fan discovered 48 previously unidentified large aftershocks from 2004 to 2015 that occurred within seconds to minutes after magnitude 7 to 8 earthquakes on faults adjacent to the mainshock ruptures.

By contrast, nearly all of the predicted afterslip for the Napa quake was completed a year after the mainshock.

Many large earthquakes are preceded by one or more foreshocks, but it is unclear how these foreshocks relate to the nucleation process of the mainshock.

The second sequence, which involved large slip rates, may have caused substantial stress loading, prompting the unstable dynamic rupture of the mainshock.

«This was an event the thrust interface of the plate boundary system, confirming that there is a subduction system in the Haida Gwaii area,» said Honn Kao, seismologist with the Geological Survey of Canada, who, along with his colleagues, examined the source parameters — causative faults, rupture processes and depths — of the mainshock and sequence of strong aftershocks.

The aftershocks clustered around the periphery of the rupture zone, both on the seaward and landward side of the plate boundary and reflected normal faulting behavior — caused by the bending, extending or stretching of rock — rather than the thrust faulting of the mainshock.

The 1997 - 98 Umbria - March seismic sequence numbered six mainshocks of moderate magnitude, ranging M 5.2 — 6.0.

«Our observations of normal faulting imply that the mainshock of the Haida Gwaii earthquake dramatically altered the stress field in the rupture zone, especially in a neighboring region,» said Kao.

· An analysis of foreshock activity by Jacob Walter of the Oklahoma Geological Survey and colleagues demonstrates a gradual fault stress increase in the months prior to the Pawnee mainshock.

Colin Pennington and Xiaowei Chen of the University of Oklahoma investigated stress interactions between the main faults in the area, concluding that the three Pawnee foreshocks promoted the failure of the fault for the Pawnee mainshock and early aftershock, and that the mainshock led to the fault failure behind further aftershocks.