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About Us

We investigate deformation of the Earth's crust due to earthquakes and volcanoes.

Measuring deformation that occurs between earthquakes constrains how much elastic strain accumulates in the crust and helps constrain future earthquake hazard.   Similarly, accumulation of magma in crustal reservoirs causes the earth's surface to swell, critical information for forecasting eruptions.  In both volcanic and tectonic environments we combine measurements with physics-based models of the relevant processes to better understand these systems.


We are investigating the physics of injection-induced seismicity including full poroelastic coupling of stress and pore pressure, and time-dependent earthquake nucleation.

We are working to unify physical-chemical models of erupting volcanoes with resulting deformation, that can be measured with GPS, InSAR, tiltmeters and other instruments.

GPS time series in northeast Japan exhibit nonlinear trends from 1996 to 2011 before the Mw 9.0, 2011 Tohoku-oki earthquake.

One of the most exciting discoveries in recent decades has been the recognition that many subduction zones undergo transient slip events at depths below the locked mega-thrust zone.

GPS position measurements are widely used for studying various geophysical phenomena  including plate movement, strain accumulation, volcanic deformation, post-glacial rebound, subsidence,  and sea-level change.  Understanding the accuracy of GPS data is therefore paramount. 

Recent Publications

Johnson, K. M.A. Mavrommatis, and P. Segall (2016), Small interseismic asperities and widespread aseismic creep on the northern Japan subduction interfaceGeophys. Res. Lett.,43, doi:10.1002/2015GL066707.

Mavrommatis, A.P., Segall, P., Uchida, N., and K.M. Johnson (2015). Long-term acceleration of aseismic slip preceding the Mw 9 Tohoku-oki earthquake: Constraints from repeating earthquakes,Geophys. Res. Lett., doi: 10.1002/2015gl066069

Schmitt, S. V.P. Segall, and E. M. Dunham (2015), Nucleation and dynamic rupture on weakly stressed faults sustained by thermal pressurizationJ. Geophys. Res. Solid Earth, , doi:10.1002/2015JB012322