Abstract: For each receiver of an array of three or more receivers monitoring a seismic event, reverse time propagation of a recorded wavefield is performed for the respective receiver to derive an extrapolated wavefield for the respective receiver. An imaging condition is applied as a crosscorrelation of the extrapolated wavefields for the three or more receivers to derive an image of the seismic event. A source of the seismic event is identified based on the image.

Abstract: Detection of repeating seismic events from long duration seismic data without prior knowledge of event waveforms is performed by computing compact binary fingerprints from seismic data, generating a similarity matrix from the fingerprints, and identifying seismic events from the similarity matrix, e.g., using a thresholding condition. Each element of the similarity matrix is a value representing similarity between a pair of fingerprints, where the value is calculated by hashing fingerprints to hash buckets in multiple hash tables and counting a fraction of the multiple hash tables containing a fingerprint match in the hash buckets. The similarity matrix may be combined with similarity matrices derived from other seismic data to produce a total network similarity matrix, increasing the sensitivity of the detection. Other seismic data may include multiple components recorded at a single station or data recorded at separately located stations.