Zheng-Kang Shen and his team have been using space geodesy methods to study crustal deformation. Based on the observations they developed models for better understanding of the tectonic deformation mechanisms and physical processes associated with earthquake cycles. The main research highlights include:

Analyzing GPS data and producing a series of crustal motion maps for southern California and western US. The results have become major products for the Southern California Earthquake Center and important data source for the production of USGS peak ground acceleration map, and have been widely cited over the years (Shen et al., 2011; Zeng and Shen, 2014; Parsons et al., 2013). The method developed to analyze campaign GPS data has become a classic method in the field. By joint analysis of GPS and terrestrial geodetic data Shen and his team successfully separated secular and postseismic deformation fields in southern California, producing the result which challenged the popular "Crème Brulee" model for rheologic structure of continental lithosphere (Liu et al., 2015). Shen and his colleagues also developed a method for mid-long term earthquake forecast using geodetic strain rates and applied that in a 5-year California earthquake forecast experiment. The test result showed that this method performed better than most of other methods participated in the experiment (Shen et al., 2007; Zechar et al., 2013). Shen and his team proposed and improved a method to derived strain rate field from GPS velocities. Application of the method to southern California helped gain new understanding of fault system deformation in the plate boundary zone driven by the tectonic stress/strain field (Shen et al., 1996, 2007, 2015).

Shen and his team applied the aforementioned GPS data analysis method to study deformation field in continental China and the surrounding region (Wang et al., 2003; Zhang et al., 2004; Gan et al., 2007), and further analyzed the results to yield a series important findings, such as: 1) precise determination of present-day India-Eurasia relative plate motion, and discovery of the corresponding error in the NUVEL1 plate motion model prediction (Shen et al., 2001). 2) Discovery and quantification of continuum deformation pattern within the Tibetan plateau (Zhang et al., 2004). 3) Discovery of deformation activity of the Longriba fault and its important role in east Tibet strain partitioning associated with eastward extrusion of the plateau (Shen et al., 2005). 4) Discovery and characterization of the deformation across the Zhangjiakou-Bohai seismic zone, providing crucial understanding of the crustal deformation pattern in North China, particularly in the “Capital Zone” region (Shen et al., 2000). 5) Precise determination of fault slip rate across the central segment of the Altyn Tagh fault, providing critical evidence for characterization of deformation pattern of the Tibetan plateau (Shen et al., 2001). 6) Precise determination of deformation pattern in south Yunnan, and discovery of a NE trending deformation zone in the region and dismissal of a previous major perception that the Red River fault was a major deformation source in the region (Shen et al., 2005). 7) Synthesized seismological, geologic, and geodetic data to develop and test multiple seismic hazard models in the Sichuan-Yunnan region, evaluated spatial and temporal feasibilities of the models, and provided mid-long term earthquake forecasts for the region (Wang et al., 2015).

Shen and his team also analyzed GPS and InSAR data and combined seismological, geologic, and geodetic results to develop model for seismogenic process and earthquake rupture of the 2008 great Wenchuan earthquake. Major findings include: 1) proposed geometric barrier model for the transpressional Longmen Shan fault, and revealed that the Wenchuan earthquake was characterized as a cascade rupture through several geometric barriers (Shen et al., 2009). 2) Based on geodetic, seismic, and geologic measurements, estimated earthquake recurrence time of the central Longmen Shan fault (Shen et al., 2009). 3) As a guest editor, participated editing of the special issue for the great Wenchuan earthquake for the Bulletin Seismological Society of America (Klinger et al., 2010). Shen's article on the coseismic rupture of the quake was published on Nature Geoscience (Shen et al., 2009), and a figure became the front cover page, and his interview was made to the back page of that issue of the magazine. The article was enlisted as one of the "research highlights" by the Nature Publishing Group.

As first author Shen has published papers with more than 1000 citations, and as second or third author he has published papers with more than 1000 citations. He was listed as one of the highly referenced authors from China by the Elsevier Publishing Group in 2014. In 2015 he is elected to the chair position for sub-commission 3.2 of Crustal Deformation, the International Association of Geodesy (IAG) for 2015-1019.

The 2009 October issue of Nature Geoscience adopted our InSAR interferogram of Wenchuan coseismic displacement field as the front cover (Shen et al., 2009).

Southern California Horizontal strain rate field interpolated from GPS velocities using a Gaussian/Voronoi weighting method developed by Shen et al. (2015). Background colors represent the second invariant and the black vector pairs the principal strain rates, respectively.

References

Gan, W., P. Zhang, Z.-K. Shen, et al., Present-day crustal motion within the Tibetan Plateau inferred from GPS measurements, J. Geophys. Res., 112, B08416, doi:10.1029/2005JB004120, 2007.

Hao, M., Q. Wang, Z. Shen*, et al., Present day crustal vertical movement inferred from precise leveling data in eastern margin of Tibetan Plateau, Tectonophysics, 632, 281-292, 2014.

Klinger Y., C. Ji, Z.-K. Shen, and W. H. Bakun (editors), Special Issue on the 2008 Wenchuan, China, Earthquake, Bull. Seism. Soc.Am., 100(5B), 2010.

Liu, S., Z.-K. Shen*, and R. Bürgmann, Recovery of secular deformation field of Mojave Shear Zone in Southern California from historical terrestrial and GPS measurements. J. Geophys. Res. Solid Earth, 120, 3965–3990. doi: 10.1002/2015JB011941, 2015.

Parsons, T., K. M. Johnson, P. Bird, J. M. Bormann, T. E. Dawson, E. H. Field, W. C. Hammond, T. A.Herring, R. McCaffrey, Z.-K. Shen, W. R. Thatcher, R. J. Weldon, II, and Y. Zeng, Appendix C: Deformation models for UCERF3, U.S. Geol. Surv. Open-File Report 2013-1165-C, and California Geol. Surv. Special Report 228-C, 2013.

Shen, Z.-K.*, M. Wang, Y. Zeng, and F. Wang, Strain determination using spatially discrete geodetic data, Bull. Seismol. Soc. Am., in press, 2015.

Shen, Z.-K.*, J. Sun, P. Zhang, Y. Wan, M. Wang, R. Bürgmann, Y. Zeng, W. Gan, H. Liao, and Q. Wang, Slip maxima at fault junctions and rupturing of barriers during the 2008 Wenchuan earthquake, Nature Geoscience, 2, 718-724, 2009.

Shen, Z.-K., R. King, D. Agnew, et al., A unified analysis of crustal motion in Southern California, 1970-2004: The SCEC Crustal Motion Map, J. Geophys. Res., 116, B11402, doi:10.1029/2011JB008549, 2011.

Shen, Z.-K.* et al., Contemporary crustal deformation around southeast borderland of Tibetan plateau, J. Geophys. Res., 110, B11409, doi:10.1029/2004JB003421, 2005.

Shen, Z.-K.*, D. D. Jackson, and Y. Y. Kagan, Implications of Geodetic Strain Rate for Future Earthquakes, With a Five-Year Forecast of M5 Earthquakes in Southern California, Seismol. Res. Lett., 78, 117-120, 2007.

Shen, Z.-K.*, M. Wang, Y. Li, D. D. Jackson, A. Yin, D. Dong, and P. Fang, GPS study of crustal deformation associated with the Altyn Tagh fault system, J. Geophys. Res., 106, 7-30,621, 2001.

Shen, Z.-K.*, C. Zhao, Y. Li, D. Jackson, P. Fang, D. Dong, and A. Yin, Contemporary crustal deformation in east Asia constrained by global positioning system measurements, J. Geophys. Res., 105, 5721-5734, 2000.

Shen, Z.-K.*, et al., Coseismic and postseismic deformation studies of the Wenchuan earthquake and seismo-tectonics of the Longmen Shan fault system, Fall Meeting, AGU, 9-13 December, 2013 (abstract, invited).

Shen, Z.-K.*, D. D. Jackson, and B. X. Ge, Crustal deformation across and beyond the Los Angeles basin from geodetic measurements, J. Geophys. Res., 101, 27,957-27,980, 1996.

Wang, M., Z. Shen*, et al., Contemporary crustal deformation of the Chinese continent and tectonic block model, Science in China (D), 46(supp.), 25-40, 2003.

Wang, F., M. Wang, Y. Wang, and Z.-K. Shen*, Earthquake potential of the Sichuan-Yunnan region, western China, J. Asian Ear. Sci., 107, 232-243, doi:10.1016/j.jseaes.2015.04.041, 2015.

Zeng, Y., and Z.-K. Shen, Fault network modeling of crustal deformation in California constrained using GPS and geologic observations, Tectonophysics, 612-613, 1-14, 2014.

Zhang, P.-Z., Z.-K. Shen et al., Continuous deformation of the Tibetan plateau from global positioning system data, Geology, 32, 809-812, 2004.

Zechar, J. D., D. Schorlemmer, M. J. Werner, et al., Regional Earthquake Likelihood Models I: First‐Order Results, Bull. Seismol. Soc. Am., 103(2A), 787-798, doi: 10.1785/0120120186, 2013.