Zhongwen Zhan (Z^2)'s Homepage

Zhongwen Zhan, Postdoctoral Researcher
Institute of Geophysics and Planetary Physics
Scripps Institution of Oceanography
University of California, San Diego

Office: IGPP, Revelle Lab, Room 3104
9500 Gilman Dr., La Jolla, CA 92093-0225
Phone: (858) 534-1543, Fax: (858) 534-5332
E-mail: zwzhan AT ucsd DOT edu

Curriculum Vitae (PDF)

Education

2002-2006 Bachelor of Science in Geophysics, Special Class for the Gifted Young, USTC
2006-2008 Master of Science in Geophysics, Department of Geophysics, USTC
2008-2013 Doctor of Philosophy in Geophysics, California Institute of Technology

News and Highlights

(07/10/2014) We have observed a supershear rupture during the 2013/05/24 Sea of Okhotsk Mw 6.7 deep earthquake, an aftershock of the 2013/05/24 Sea of Okhotsk Mw 8.3 earthquake. The supershear 2013 Sea of Okhotsk earthquake had similar magnitude and fault geometry as the damaging 1994 Northridge earthquake in California, but a much larger depth and faster rupture speed. The high rupture speed (~8 km/s) away from the hypocenter, shown as the red star, concentrates strong shaking on the Mach front.

For more details, please read: Science, Scripps News, Live Science, Yahoo, Phys.org, GlobalPost, XinhuaNet, 新华网, (e) science, Science Codex, RedOrbit.

Research Interests

My research interests lie in the broad area of seismology and emphasize two geophysical research topics, ambient seismic noise and subduction zone processes.

I. Ambient seismic noise

Ambient seismic noise reflects the interactions among Earth’s spheres (e.g., atmosphere-ocean-solid Earth) and makes up the largest portion of most continuous seismic records. This huge dataset, once treated as “noise”, is now providing valuable constraints on Earth’s shallow structure through cross-correlation. In the noise correlation method, receivers are treated as virtual sources to sample receiver-receiver paths. This greatly expands the scope of traditional seismology of earthquake-receiver paths. Seismic noise’s rich information about deep-Earth structure and surface processes responsible for noise generation has just begun to be explored. I am mostly interested in:

1. Retrieving body waves from noise cross-correlations on dense arrays

2. Studying glacier structures using the noise correlation method

 

II. Subduction zone processes

Subduction zones provide most of the driving forces of plate tectonics and produce many large earthquakes from very shallow depths to the bottom of the upper mantle. The fundamental questions, “how do great earthquakes rupture,” and “what controls large earthquakes,” remain open. I am interested in approaching these questions by providing a better seismological picture of large earthquake rupture processes and the subduction zone environment in which they occur. More specifically, I am interested in:

1. Rupture processes of shallow and deep large earthquakes

2. Fine-scale mega-thrust fault zone structures from small earthquakes

3. Subducted slab structures using regional and teleseismic waveforms

Publications

  1. Zhan, Z., D. Helmberger, H. Kanamori, and P. Shearer (2014). Supershear rupture in a Mw 6.7 aftershock of the 2013 Sea of Okhotsk earthquake, Science, In Press. DOI: 10.1126/science.1252717. Full Text
  2. Riel, B., Simons, M., Agram, P., and Zhan, Z. (2014) Detecting transient signals in geodetic time series using sparse estimation techniques, J. Geophys. Res., Published online, DOI: 10.1002/2014JB011077
  3. Zhan, Z., D. Helmberger, and D. Li (2014). Imaging subducted slab structure beneath the Sea of Okhotsk with teleseismic waveforms, Phys. Earth Planet. In., 232, 30-35. DOI: 10.1016/j.pepi.2014.03.008. PDF
  4. Zhan, Z., V. C. Tsai, J. Jackson, and D. Helmberger (2014). Ambient noise correlation on the Amery Ice Shelf, East Antarctica, Geophys. J. Int., 196, 1796-1802. DOI: 10.1093/gji/ggt488. PDF
  5. Zhan, Z., H. Kanamori, V. C. Tsai, D. Helmberger, and S. Wei (2014). Rupture complexity of the 1994 Bolivia and 2013 Sea of Okhotsk deep earthquakes, Earth Planet. Sci. Lett., 385, 89-96. DOI: 10.1016/j.epsl.2013.10.028. PDF
  6. Wei, S., D. Helmberger, Z. Zhan, and R. Graves (2013). Rupture complexity of the Mw 8.3 Sea of Okhotsk earthquake: Rapid triggering of complementary earthquakes? Geophys. Res. Lett., 40(1-6). PDF
  7. Zhan, Z., V. C. Tsai, and R. W. Clayton (2013). Spurious velocity changes caused by temporal variations in ambient noise frequency content, Geophys. J. Int., 194(3). 1574-1581. PDF
  8. Lin, F.-C., V. C. Tsai, B. Schmandt, Z. Duputel, and Z. Zhan (2013). Extracting seismic core phases with array interferometry, Geophys. Res. Lett., 40(6). 1049-1053. PDF
  9. Nemati, M., J. Hollingsworth, Z. Zhan, M. J. Bolourchi, and M. Talebian (2013). Microseismicity and seismotectonics of the South Caspian Lowlands, NE Iran, Geophys. J. Int., 193(3). 1053-1070. PDF
  10. Ma, Y., R. W. Clayton, V. Tsai, and Z. Zhan (2013). Locating a scatterer in the active volcanic area of Southern Peru from ambient noise cross-correlation, Geophys. J. Int., 192(3). 1332-1341. PDF
  11. Zhan, Z., D. Helmberger, M. Simons, H. Kanamori, W. Wu, N. Cubas, Z. Duputel, R. Chu, V. C. Tsai, J.-P. Avouac, K. W. Hudnut, S. Ni, E. Hetland, and F.H.O. Culaciati (2012). Anomalously steep dips of earthquakes in the 2011 Tohoku-Oki source region and possible explanations, Earth Planet. Sci. Lett., 353-354, 121-133. PDF
  12. Wei, S., Z. Zhan, Y. Tan, S. Ni and D. Helmberger (2012). Locating earthquakes with surface waves and centroid moment tensor estimation, J. Geophys. Res., 117, B04309. PDF
  13. Zhan, Z., B. Jin, S.Wei, and R. W. Graves (2011). Coulomb stress change sensitivity due to variability in mainshock source models and receiving fault parameters: a case study of the 2010-2011 Christchurch, New Zealand earthquakes, Seismo. Res. Lett., 82(6). 800-814. PDF
  14. Chu, R., S. Wei, D. V. Helmberger, Z. Zhan, L. Zhu, and H. Kanamori (2011). Initiation of the great Mw 9.0 Tohoku-Oki earthquake, Earth Planet. Sci. Lett., 308(3-4). 277-283. PDF
  15. Zhan, Z., S. Wei, S. Ni, and D. Helmberger (2011). Earthquake centroid locations using calibration from ambient seismic noise, Bull. Seismo. Soc. Am., 101(3). 1438-1445. PDF
  16. Xie, J., X. Zeng, W. Chen, and Z. Zhan (2011). Comparison of ground truth location of earthquake from InSAR and from ambient seismic noise: A case study of the 1998 Zhangbei earthquake, Earthquake Science, 24, 239-247. PDF
  17. Zeng, X., Z. Zhan, and Y. Zheng (2011). Estimated Green’s function extracted from superconducting gravimeters and seismometers, Earthquake Science, 24, 143-150. PDF
  18. Zhan, Z., S. Ni (2010). Stationary phase approximation in the ambient noise method revisited, Earthquake Science, 23 (5). 425-431. PDF
  19. Luo, Y., Y. Tan, S. Wei, D. Helmberger, Z. Zhan, S. Ni, E. Hauksson, and Y. Chen (2010). Source mechanism and rupture directivity of the May 18, 2009 Mw4.6 Inglewood, California earthquake, Bull. Seismo. Soc. Am., 100 (6). 3269-3277. PDF
  20. Zhan, Z., S. Ni, D. Helmberger and R. W. Clayton (2010). Retrieval of Moho-reflected shear wave arrivals from ambient seismic noise, Geophys. J. Int., 182 (1). 408-420. PDF
  21. Zhan, Z., and C. Chen (2006). Estimates of Europa’s ice shell thickness and strain rate from flanking cracks and bulge along Ridge R, Sci. China Ser. G, 49 (6). 748-756. PDF
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