Export 3 results:
Sort by: Author Title Type [ Year  (Desc)]
Donner, S, Lin CJ, Hadziioannou C, Gebauer A, Vernon F, Agnew DC, Igel H, Schreiber U, Wassermann J.  2017.  Comparing direct observation of strain, rotation, and displacement with array estimates at Pinon Flat Observatory, California. Seismological Research Letters. 88:1107-1116.   10.1785/0220160216   AbstractWebsite

The unique instrument setting at the Pinon Flat Observatory in California is used to simultaneously measure 10 out of the 12 components, completely describing the seismic-wave field. We compare the direct measurements of rotation and strain for the 13 September 2015 M-w 6.7 Gulf of California earthquake with array-derived observations using this configuration for the first time. In general, we find a very good fit between the observations of the two measurements with cross-correlation coefficients up to 0.99. These promising results indicate that the direct and array-derived measurements of rotation and strain are consistent. For the array-based measurement, we derived a relation to estimate the frequency range within which the array-derived observations provide reliable results. This relation depends on the phase velocity of the study area and the calibration error, as well as on the size of the array.

Fialko, Y, Sandwell D, Agnew D, Simons M, Shearer P, Minster B.  2002.  Deformation on nearby faults induced by the 1999 Hector Mine earthquake. Science. 297:1858-1862.   10.1126/science.1074671   AbstractWebsite

Interferometric Synthetic Aperture Radar observations of surface deformation due to the 1999 Hector Mine earthquake reveal motion on several nearby faults of the eastern California shear zone. We document both vertical and horizontal displacements of several millimeters to several centimeters across kilometer-wide zones centered on pre-existing faults. Portions of some faults experienced retrograde (that is, opposite to their long-term geologic slip) motion during or shortly after the earthquake. The observed deformation likely represents elastic response of compliant fault zones to the permanent co-seismic stress changes. The induced fault displacements imply decreases in the effective shear modulus within the kilometer-wide fault zones, indicating that the latter are mechanically distinct from the ambient crustal rocks.

Johnson, HO, Agnew DC, Hudnut K.  1994.  Extremal Bounds on Earthquake Movement from Geodetic Data - Application to the Landers Earthquake. Bulletin of the Seismological Society of America. 84:660-667. AbstractWebsite

We present a technique to place quantifiable bounds on the moment of an earthquake from geodetic data, assuming known fault geometry. Application of this technique to the 1992 Landers earthquake shows that the moment must have been between 0.84 and 1.15 x 10(20) Nm with 90% confidence (M 7.25 to 7.34). We also find that to satisfy the data to this same level of confidence, the slip on the fault must have exceeded 7 m in at least one location, in good agreement with field mapping of the surface rupture.