Dilational processes accompanying earthquakes in the long valley caldera

نویسندگان

  • Dreger
  • Tkalcic
  • Johnston
چکیده

Regional distance seismic moment tensor determinations and broadband waveforms of moment magnitude 4.6 to 4.9 earthquakes from a November 1997 Long Valley Caldera swarm, during an inflation episode, display evidence of anomalous seismic radiation characterized by non-double couple (NDC) moment tensors with significant volumetric components. Observed coseismic dilation suggests that hydrothermal or magmatic processes are directly triggering some of the seismicity in the region. Similarity in the NDC solutions implies a common source process, and the anomalous events may have been triggered by net fault-normal stress reduction due to high-pressure fluid injection or pressurization of fluid-saturated faults due to magmatic heating.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

New constraints on mechanisms of remotely triggered seismicity at Long Valley Caldera

[1] Regional-scale triggering of local earthquakes in the crust by seismic waves from distant main shocks has now been robustly documented for over a decade. Some of the most thoroughly recorded examples of repeated triggering of a single site from multiple, large earthquakes are measured in geothermal fields of the western United States like Long Valley Caldera. As one of the few natural cases...

متن کامل

Observation of di usion processes in earthquake populations , and implications on the predictability of seismicity systems

Scale invariance, either in space or in time, has been shown in many papers to characterize earthquake distributions. Unfortunately, only little work has been dedicated to looking at the general space-time scaling invariance of seismicity systems, even though a better understanding of how the two domains (spatial and temporal) link together could help to the development of the stochastic dynami...

متن کامل

Remotely Triggered Seismicity on the United States West Coast following the Mw 7.9 Denali Fault Earthquake

The Mw 7.9 Denali fault earthquake in central Alaska of 3 November 2002 triggered earthquakes across western North America at epicentral distances of up to at least 3660 km. We describe the spatial and temporal development of triggered activity in California and the Pacific Northwest, focusing on Mount Rainier, the Geysers geothermal field, the Long Valley caldera, and the Coso geothermal field...

متن کامل

Absence of Evidence for a Shallow Magma Chamber beneath Long Valley Caldera, California, in Downhole and Surface Seismograms

A downhole seismometer at 900-m depth and a temporary network of surface stations were deployed to use rays from local microearthquakes to study the upper and middle crust beneath the Long Valley caldera. The downhole seismograms show S waves with high apparent amplitudes from earthquakes located 2-20 km to the south of the downhole seismometer. In contrast, S waves from earthquakes located in ...

متن کامل

Monitoring super-volcanoes: geophysical and geochemical signals at Yellowstone and other large caldera systems.

Earth's largest calderas form as the ground collapses during immense volcanic eruptions, when hundreds to thousands of cubic kilometres of magma are explosively withdrawn from the Earth's crust over a period of days to weeks. Continuing long after such great eruptions, the resulting calderas often exhibit pronounced unrest, with frequent earthquakes, alternating uplift and subsidence of the gro...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Science

دوره 288 5463  شماره 

صفحات  -

تاریخ انتشار 2000