oa Using Spectral Attributes to Detect Seismic Tremor Sources - A Synthetic Study

A method is presented to detect subsurface seismic tremor sources by analyzing surface data. Spectral<br>attributes of the recorded seismic wave-field at low frequencies are used to map the surface projection<br>of the sources. We illustrate the concept on a synthetic data-set generated with a homogenous forward<br>model and show how spectral attributes can be used for detecting locations of seismic tremor sources.<br>In a second part we apply the method to an example of hydrocarbon reservoir related tremors. The<br>results show that increased complexity of the subsurface seismic properties and/or the presence of<br>several tremor sources can strongly complicate the interpretation. In addition, the presence of<br>dominant surface noise may mask the signals emitted by the subsurface tremor sources and make it<br>impossible to detect them at the surface without additional processing. F-K filtering is successfully<br>applied to noise-contaminated data and retrieves masked anomalies. Care has to be taken for using a<br>proper data-set and proper processing parameters in order to avoid artifacts introduced by the F-K<br>filter. Although we discuss an application for possible hydrocarbon reservoir related tremors, we<br>believe that the methods can also be applied to any other type of seismic tremor signal.