Pure and Applied Geophysics

, Volume 165, Issue 8, pp 1577–1602 | Cite as

Postseismic Deformation Following the 1994 Northridge Earthquake Identified Using the Localized Hartley Transform Filter

  • K. F. Tiampo
  • Dawit Assefa
  • J. Fernández
  • L. Mansinha
  • H. Rasmussen
Article

Abstract

Here we present a new mathematical tool, the localized Hartley (HL) transform (Hartley, 1942; Bracewell, 1990), that allows for the filtering of 1-D time series through the identification of the power at various spatial and temporal wavelengths. Its application to and the associated results are presented from its application to continuous Global Positioning System (GPS) data from southern California for the time period 1994 through 2006. The HL transform filter removes the high-frequency components of the data and effectively isolates the longer period signal. This long-period signal is modeled as time-dependent postseismic deformation using the viscoelastic-gravitational model of Fernández and Rundle (2004) for six stations selected for their proximity to the Northridge earthquake. The x-, y-, and z-components of the postseismic deformation are compared to the filtered data. Results suggest that this long-period deformation is a result of postseismic relaxation and that the HL transform filter provides an important new technique for the filtering of geophysical data consisting of the superposition of the effects of numerous complex sources at a variety of spatial and temporal scales.

Keywords

Hartley transform GPS time series analysis spatio-temporal filtering postseismic deformation Northridge earthquake 

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Copyright information

© Birkhaueser 2008

Authors and Affiliations

  • K. F. Tiampo
    • 1
  • Dawit Assefa
    • 2
  • J. Fernández
    • 3
  • L. Mansinha
    • 1
  • H. Rasmussen
    • 4
  1. 1.Department of Earth SciencesUniversity of Western OntarioLondonCanada
  2. 2.Radiation Physics Department, Radiation Medicine ProgramPrincess Margaret HospitalTorontoCanada
  3. 3.Institutio de Astronomía y Geodesia (CSIC-UCM), Facultad de CC. MatemáticasCiudad UniversitariaMadridSpain
  4. 4.Department of Applied MathematicsThe University of Western OntarioLondonCanada

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