Shallow locking depth in the Eastern California Shear Zone, significance for low angle normal faulting.
Noel Gourmelen(1), Falk Amelung(1), Mariarosaria Manzo(2), Francesco Casu(2), Riccardo Lanari(2), Kaj Johnson(3) and Eric Bergman(4)
(1) University of Miami, 4600 Rickenbacker Causeway, 33149, Miami, United States
(2) CNR, via Diocleziano, 328, 80124 Napoli, Italy
(3) Indiana University, 1001 E. 10th St., Bloomington, IN 47405, United States
(4) University of Colorado Boulder, University of Colorado - Boulder, 80309, Boulder, United States
The Panamint Valley – Hunter Mountain – Saline Range (PHS) faults are, together with the Death Valley and Owens Valley faults, one of the three major fault zones within the Eastern California Shear Zone (ECSZ). The ECSZ is the most active fault system bounding the Basin and Range to the southwest with approximately 10 mm/yr of cumulative slip along strike-slip and trans-tensional segments. Previous work has identified the Panamint Valley and Saline Range faults as low angle normal faults and the Hunter Mountain as a transfer fault (Wesnousky and Jones, 1994). A debate exists whether this system is active at present time.
Interferometry Synthetic Aperture Radar (InSAR) is a geodetic technique that allows measurement of ground motion at a mm/yr accuracy over large areas with a high measurement sampling. We processed a large number of data to investigate ground motion in the PHS fault system to shed light on the interseismic strain accumulation and its relation to the fault geometry.
Preliminary results indicate high strain rate over the Hunter Mountain fault. The locking depth of the fault inferred from elastic modeling of interseismic strain accumulation is on the order of 4km, significantly shallower than for neighboring faults. In contrast, the long wavelength strain field across the Panamint and Saline faults indicates possibly deeper locking depths and/or shallower dip. The shallow locking depth of 4km inferred for the Hunter Mountain fault corresponds with the extension at depth of the two bounding low angle normal faults below Hunter Mountain, suggesting a control of the low angle normal fault system.
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,