Machine learning in microseismic monitoring

The confluence of our ability to handle big data, significant increases in instrumentation density and quality, and rapid advances in machine learning (ML) algorithms have placed Earth Sciences at the threshold of dramatic progress. ML techniques have been attracting increased attention within the seismic community, and, in particular, in...

Integrating earthquake-based passive seismic methods in mineral exploration: Case study from the Gerolekas bauxite mining area, Greece

As the global need for aluminum constantly rises, bauxite is considered to be a critical mineral, and the mining industry is in search of new and effective exploration solutions. In this context, we design and implement a purely earthquake-based passive seismic survey at the Gerolekas bauxite mining site in Greece. It is a very difficult...

Towards adapting reverse vertical seismic profiling for ambient-noise imaging with transient sources: Automatic estimation of stationary-phase receivers for improved retrieval of the interferometric Green's function

Most of the ambient-noise studies are performed with sensor arrays located at the surface. Passive recordings containing seismic arrivals from subsurface sources could be seen as having a geometry resembling reverse vertical seismic profiling (RVSP). In such scenarios, the intersource seismic-interferometry technique can be used to redatum...

Earthquake-based passive seismic exploration techniques

Passive seismic surveys have long been applied in the context of exploration studies. Our research focuses on the exploitation of the natural seismicity that is present in passive seismic records and the extraction of useful information of the subsurface from different parts of the earthquake signal. In that scope, we initially install a dense...

Studying CO2 storage with ambient-noise seismic interferometry: A combined numerical feasibility study and field-data example for Ketzin, Germany

Seismic interferometry applied to ambient-noise measurements allows the retrieval of the seismic response between pairs of receivers. We studied ambient-noise seismic interferometry (ANSI) to retrieve time-lapse reflection responses from a reservoir during CO2 geologic sequestration, using the case of the experimental site of Ketzin, Germany. We...

The potential of imaging subsurface heterogeneities by local, natural earthquakes

We have developed a new imaging technique of subsurface heterogeneities that uses Sp-waves from natural earthquakes. This technique can be used as a first screening tool in frontier exploration areas before conventional active exploration. Analyzing Sp-waves from 28 earthquakes (Mj 2.0 to 4.2) recorded by two permanent seismic stations, we built...

Experiences with a Permanently Installed Seismic Monitoring Array at the CO2 Storage Site at Ketzin (Germany): A Status Overview

Since July 2008, CO2 is injected into a saline aquifer near the town of Ketzin in Germany. For monitoring the CO2- migration close to the injection well, TNO installed a fixed 2D seismic array of 120 meters length in 2009, with 3- component geophones at the surface, 4-component receivers at 50 meters depth and a central vertical array of 4-...

Finite-difference modeling experiments for seismic interferometry

In passive seismic interferometry, new reflection data can be retrieved by crosscorrelating recorded noise data. The quality of the retrieved reflection data is, among others, dependent on the duration and number of passive sources present during the recording time, the source distribution, and the source strength. To investigate these relations...

Estimation of Primaries and Multiples by Sparse Inversion

Surface-related multiple reflections are often considered noise in the seismic reflection measurements. By seismic processes, such as migration and inversion, they can be mistakenly seen as primary reflections and give an erroneous image of the earth. Therefore, a method is needed to separate the multiples from the primaries. This thesis...