Speaker
Description
The resonance seismometry is one of the CTBT’s permitted techniques during an on-site inspection (OSI). In order to enhance the capabilities of the OSIs, we have developed a method for detecting a deep underground cavity based on the analysis of seismic ambient noise data called the Finite-Interval Spectral Power (FISP). The FISP method has become part of the draft of Concept of Operations for Resonance Seismometry. The mapping of FISP values enables the identification of the horizontal position of the cavity. The method employs single-station measurements at potentially irregularly distributed points on the Earth's free surface within the suspected cavity's area. The minimum number of receivers is 2. The grid of measurement points can be densified later if necessary.
The FISP method has so far been applied to noise recordings above cavities at four different locations and environments, with different cavity depths and dimensions. We present our findings, along with the further development of the FISP method. The minimum standards required for noise measurements and instrumentation for FISP are also discussed.
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