Fred F Pollitz

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The relation between the complex geological history of the western margin of the North American plate and the processes in the mantle is still not fully documented and understood. Several pre-USArray local seismic studies showed how the characteristics of key geological features such as the Colorado Plateau and the Yellowstone Snake River Plains are linked(More)
Large earthquakes trigger very small earthquakes globally during passage of the seismic waves and during the following several hours to days, but so far remote aftershocks of moment magnitude M ≥ 5.5 have not been identified, with the lone exception of an M = 6.9 quake remotely triggered by the surface waves from an M = 6.6 quake 4,800 kilometres away. The(More)
[1] New seismic and geodetic data from Costa Rica provide insight into seismogenic zone processes in Central America, where the Cocos and Caribbean plates converge. Seismic data are from combined land and ocean bottom deployments in the Nicoya peninsula in northern Costa Rica and near the Osa peninsula in southern Costa Rica. In Nicoya, inversion of GPS(More)
a r t i c l e i n f o a b s t r a c t USArray has facilitated significant advancement in tomographic models and methodologies. While there persists a fundamental tradeoff between horizontal and vertical resolution due to the components of the wave train analyzed, advances in joint inversions are continuing to refine the tomographic images generated with(More)
Results from different tsunami forecasting and hazard assessment models are compared with observed tsunami wave heights from the 26 December 2004 Indian Ocean tsunami. Forecast models are based on initial earthquake information and are used to estimate tsunami wave heights during propagation. An empirical forecast relationship based only on seismic moment(More)
The analysis of GRACE gravity data revealed postseismic gravity increase by 6 μGal over a 500 km scale within a couple of years after the 2011 Tohoku-Oki earthquake, which is nearly 40–50% of the coseismic gravity change. It originates mostly from changes in the isotropic component corresponding to the M rr moment tensor element. The exponential decay with(More)
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