Yucca Mountain Rapid Coseismic Offset Calculator

Overview

The Yucca Mountain Rapid Coseismic Offset Calculator is designed to provide rapid estimates of GPS station displacements at Yucca Mountain, NV, as a result of regional seismic activity. Events which have recently triggered the calculator are listed at the bottom of this page, along with links to estimation output. A description of the process, caveats, and contact information is given directly below.

Methodology

The calculator is invoked if an earthquake of a certain magnitude occurs within a defined proximity of the centroid of Yucca Mountain. The larger the earthquake magnitude, the greater the proximity which will trigger the Calculator.

Displacements observed at Yucca Mountain GPS stations are estimated 5 days after a trigger event by automated processing scripts using data from 6 days prior to the event and 4 days after the event. GPS data used are a subset of BARGEN and 6 widespread "stable" North America stations (used in reference frame stabilization). Position time series estimates are determined with the GAMIT / GLOBK software package using dual-frequency measurements, fixing carrier phase ambiguities, and estimating orbital parameters, neutral atmosphere zenith and gradient terms and daily station positions.

Typical uncertainties for this network, using this quantity of data, with the described processing is on the order of 1 mm (1 sigma) in the horizontal components. Station coordinate component offsets and associated uncertainties are estimated from the pre- / post-event time series of each station. Outputs include a figure of horizontal offset vectors and uncertainties, a table of horizontal and vertical estimates and the computed time series for all stations - each of which are available for download.

Caveats

Please note that the results presented here represent rapid geodetic solutions, designed as indicators of the effect of regional seismic activity on the Yucca Mountain GPS cluster. Therefore, results are not final, and vector offset estimates must be taken within context of their associated error estimates.

Triggering Events and Results

2006 Jan 29 (test)

2005 Nov 23 (test)

For further information contact:

Yucca Mt. Questions
Harvard-Smithsonian Center for Astrophysics
60 Garden St, MS 42
Cambridge, MA 02138-1516
(617) 496-6268