Hydroacoustic monitoring of the Comprehensive Nuclear Test Ban Treaty (CTBT) requires the ability to detect and locate phenomena that give rise to acoustic signals. An improved understanding of the coupling of seismic energy to acoustic energy is necessary to improve location estimates of earthquakes and volcanic eruptions. Using known variations in near-source bathymetry, the authors demonstrated that scattering of seismic to acoustic energy at a rough seafloor yields the approximate ...
This report presents the results of a study of the coupling of seismic energy to the SOFAR channel and the propagation of acoustic energy from source to receiver. The results of an investigation of T-phase amplitude level vs. earthquake magnitude are presented for events in the Pacific ocean. The poor correlation between these parameters suggests that the generation of detectable T-phases is dependent not only upon event magnitude and depth, ...
The CTBT negotiations have endowed small seismo/acoustic events (mb ^ 2.5) with a much greater significance than they have had in the past and have increased the need for automated regional discrimination. We have been contracted by AFTAC to develop a small event discriminant that uses a time frequency expansion (sonogram) of seismic coda to discriminate ripple fired mining explosions from single explosions and earthquakes. The Automated Time Frequency Discriminant ...
The current demand for large spatial armys of seafloor instruments and deployment times of up to 12 months can be best fulfilled by inexpensive, low-power data loggers with modern commercial magnetic disk drives for on-board mass storage. We recently designed, constructed, tested, and used 6 seafloor data loggers equipped with hydrophones for seismic refraction experiments on the Clipperton Fracture Zone and Australian-Antarctic Discordance. The instruments are based on Onset's Tattletale ...
Reports by Author
