Dr. Sjoerd de Ridder, Research Fellow at the University of Edinburgh, presents "Seismic noise gradiometry for surface-wave azimuthal anisotropy" at the MIT Earth Resources Laboratory on March 4, 2016.

"Knowledge of the subsurface stress state is key to understand a host of earth-science issues such as earthquake hazards, induced seismicity, drilling-hazards, shallow-gas hazards, etc. To understand the temporal evolution of these phenomena we need to monitor the subsurface for short time-scale variations. To this end, I study seismic noise wavefield gradiometry and it’s application in a dense large N industrial array. Elliptically anisotropic phase velocities of surface waves are derives from spatial and temporal gradients of a seismic noise wavefield, using as little as a few minutes of noise recording. The azimuthal anisotropy forms a circular geometry around the production induced subsidence bowl."