Fault Zone Imaging from Correlations of Aftershock Waveforms
- 107 Downloads
We image an active fault zone environment using cross correlations of 154 15 s long 1992 Landers earthquake aftershock seismograms recorded along a line array. A group velocity and phase velocity dispersion analysis of the reconstructed Rayleigh waves and Love waves yields shear wave velocity images of the top 100 m along the 800 m long array that consists of 22 three component stations. Estimates of the position, width, and seismic velocity of a low-velocity zone are in good agreement with the findings of previous fault zone trapped waves studies. Our preferred solution indicates the zone is offset from the surface break to the east, 100–200 m wide, and characterized by a 30% velocity reduction. Imaging in the 2–6 Hz range resolves further a high-velocity body of similar width to the west of the fault break. Symmetry and shape of zero-lag correlation fields or focal spots indicate a frequency and position dependent wavefield composition. At frequencies greater than 4 Hz surface wave propagation dominates, whereas at lower frequencies the correlation field also exhibits signatures of body waves that likely interact with the high-velocity zone. The polarization and late arrival times of coherent wavefronts observed above the low-velocity zone indicate reflections associated with velocity contrasts in the fault zone environment. Our study highlights the utility of the high-frequency correlation wavefield obtained from records of local and regional seismicity. The approach does not depend on knowledge of earthquake source parameters, which suggests the method can return images quickly during aftershock campaigns to guide network updates for optimal coverage of interesting geological features.
KeywordsFault zones Imaging Surface waves Cross-correlation Aftershocks
We thank Z. Peng for help with the database and M. Wathelet, A. Mordret, and D. Faulkner for discussions. We thank the Editor B. Edwards, reviewer P.-E. Share, and an anonymous reviewer for comments that helped to improve the manuscript. G. Hillers acknowledges support through a Heisenberg fellowship from the German Research Foundation (HI 1714/1-2). M. Campillo acknowledges support from Institut Universitaire de France. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant Agreement No. 742335, F-IMAGE). Most figures are made using the Generic Mapping Tools (Wessel and Smith 1998).
- Aki, K. (1957). Space and time spectra of stationary stochastic waves, with special reference to microtremors. Bulletin of the Earthquake Research Institute, The University of Tokyo, 35, 415–457.Google Scholar
- Ben-Zion, Y., & Aki, K. (1990). Seismic radiation from an SH line source in a laterally heterogeneous planar fault zone. Bulletin of the Seismological Society of America, 80(4), 971–994.Google Scholar
- Campillo, M., & Paul, A. (2003). Long-range correlations in the diffuse seismic coda. Science. https://doi.org/10.1126/science.1078551.
- Campillo, M., Singh, S. K., Shapiro, N., Pacheco, J., & Herrmann, R. B. (1996). Crustal structure south of the Mexican volcanic belt, based on group velocity dispersion. Geofísica Internacional, 35, 361–370.Google Scholar
- Catheline, S., Benech, N., Brum, J., & Negreira, C. (2008). Time reversal of elastic waves in soft solids. Physical Review Letters, 100(6), 064301. https://doi.org/10.1103/PhysRevLett.100.064301.
- Chaput, J., Campillo, M., Aster, R. C., Roux, P., Kyle, P. R., Knox, H., et al. (2015). Multiple scattering from icequakes at Erebus volcano, Antarctica; Implications for imaging at glaciated volcanoes. Journal of Geophysical Research, 120, 1129–1141. https://doi.org/10.1002/2014JB011278.Google Scholar
- Fang, H., Zhang, H., Yao, H., Allam, A., Zigone, D., & Ben-Zion, Y., et al. (2016). A new algorithm for three-dimensional joint inversion of body wave and surface wave data and its application to the Southern California plate boundary region. Journal of Geophysical Research: Solid Earth. https://doi.org/10.1002/2015JB012702.
- Haberland, C., Agnon, A., El-Kelani, R., Maercklin, N., Qabbani, I., & Rümpker, R., et al. (2003). Modeling of seismic guided waves at the Dead Sea Transform. Journal of Geophysical Research. https://doi.org/10.1029/2002JB002309.
- Hauksson, E., Jones, L. M., Hutton, K., & Eberhart-Phillips, D. (1993). The 1992 Landers earthquake sequence: Seismological observations. Journal of Geophysical Research, 98(B11), 19,835–19,858Google Scholar
- Herrmann, R. B. (2006). Computer programs in seismology, vers. 3.30; An overview of synthetic seismogram computation. Tech. rep., Saint Louis University. http://www.eas.slu.edu/People/RBHerrmann/ComputerPrograms.html
- Hillers, G., Roux, P., Campillo, M., & Ben-Zion, Y. (2016). Focal spot imaging based on zero lag cross correlation amplitude fields: Application to dense array data at the San Jacinto fault zone. Journal of Geophysical Research: Solid Earth. https://doi.org/10.1002/2016JB013014.
- Jones, C., Nippress, S., Rietbrock, A., Faulkner, D. R., Rutter, E. H., Haberland, C. A., & Teixido, T. (2010). The shallow velocity structure of the Carboneras fault zone from high-resolution seismic investigations. AGU Fall Meeting Abstracts. Abstract T41B-2111Google Scholar
- Kurzon, I., Vernon, F. L., Ben-Zion, Y., & Atkinson, G. (2014). Ground motion prediction equations in the San Jacinto fault zone—significant effects of rupture directivity and fault zone amplification. Pure and Applied Geophysics. https://doi.org/10.1007/s00024-014-0855-2.
- Li, Y. G., Aki, K., Adams, D., Hasemi, A., & Lee, W. H. K. (1994a) Seismic guided waves trapped in the fault zone of the Landers, California, earthquake of 1992. Journal of Geophysical Research, 99(B6):11,705–11,722Google Scholar
- McGuire, J., & Ben-Zion, Y. (2005). High-resolution imaging of the Bear Valley section of the San Andreas Fault at seismogenic depths with fault-zone head waves and relocated seismicity. Geophysical Journal International, 163, 152–164. https://doi.org/10.1111/j.1365-246X.2005.02703.x.CrossRefGoogle Scholar
- Mordret, A., Shapiro, N. M., Singh, S. S., Roux, P., & Barkved, O. I. (2013). Helmholtz tomography of ambient noise surface wave data to estimate Scholte wave phase velocity at Valhall Life of the Field. Geophysics, 78(2), WA99–WA109. https://doi.org/10.1190/GEO2012-0303.1.
- Ozakin, Y., Ben-Zion, Y., Aktar, M., Karabulut, H., & Peng, Z. (2012). Velocity contrast across the 1944 rupture zone of the North Anatolian fault east of Ismetpasa from analysis of teleseismic arrivals. Geophysical Research Letters, 39, L08307. https://doi.org/10.1029/2012GL051426.CrossRefGoogle Scholar
- Roux, P., Moreau, L., Lecointre, A., Hillers, G., Campillo, M., Ben-Zion, Y., et al. (2016). A methodological approach towards high-resolution seismic imaging of the San Jacinto Fault Zone using ambient-noise recordings at a spatially dense array. Geophysical Journal International, 206, 980–992. https://doi.org/10.1093/gji/ggw193.CrossRefGoogle Scholar
- Seydoux, L., Shapiro, N., de Rosny, J., & Landès, M. (2015). A spatial coherence analysis of seismic wavefields based on array covariance matrix: Application to one year of USArray data. Eos Trans AGU Fall Meet. Suppl., Abstract S34B-04Google Scholar
- Thurber, C., Zhang, H., Waldhauser, F., Hardebeck, J., Michael, A., & Eberhart-Phillips, D. (2006). Three-dimensional compressional wavespeed model, earthquake relocations, and focal mechanisms for the Parkfield, California. Region Bulletin of the Seismological Society of America, 96(4B), S38–S49.CrossRefGoogle Scholar
- Wald, D. J., & Heaton, T. H. (1994). Spatial and temporal distribution of slip for the 1992 Landers, California, earthquake. Bulletin of the Seismological Society of America, 84(3), 668–691.Google Scholar
- Wessel, P., & Smith, W. H. F. (1998). New, improved version of generic mapping tools released. Eos Trans AGU. https://doi.org/10.1029/98EO00426.