Modeling and observations for Resonance Seismometry

We study the interaction of a seismic wave-field with a spherical acoustic gas-or fluid-filled cavity. The intention of this study is to identify characteristic features in the interaction that may help detecting cavities in the subsurface. This is important for many applications, as in particular the detection of underground nuclear explosions which are to be prohibited by the Comprehensive-Test-Ban-Treaty (CTBT). On-Site Inspections (OSI) should assure possible violations of the CTBT to be convicted if suspicious seismic events that may have been caused by nuclear explosions are detected by the international monitoring system (IMS). One primary structural target for the field team during an OSI is the detection of cavities created by underground nuclear explosions. As one seismological technique resonance seismometry is mentioned in the treaty which refers to detection of cavity-resonances but also includes the detection of structural anomalies by other passive seismic techniques.