Marcellus natural gas trend Experts believe that these were induced seismicity triggered by disposal of wastewater from Marcellus gas wells into Class II underground injection wells. The Ohio Department of Natural Resources Ohio Seismic Network (OhioSeis) determined that the 2011 earthquakes are distinct from previous seismic activity in the region because of their proximity to the Northstar 1, a Class II deep injection well. All of the earthquakes were clustered less than a mile around the well. ODNR then ordered the company to shut down operations and plug the well. ODNR has continued to report increased seismic activity through 2017 in eastern Ohio in
Seismic interferometry used to estimate ground roll to aid in its removal. Seismic interferometry simplifies estimates of shear wave velocity and attenuation in a standing building. Seismic interferometry has been applied to image the seismic scattering and velocity structure of volcanoes. Increasingly, seismic interferometry is finding a place in exploration and production. SI can image dipping sediments adjacent to salt domes. Complex salt geometries are poorly resolved using traditional seismic reflection techniques. An alternative method calls for the use of downhole sources and receivers adjacent to subsurface salt features. It is often difficult to generate an ideal seismic signal in a downhole