Application of the newly constructed Chirp SBP recording system for raw data with phase information for the study of shallow gas in Korea Strait shelf mud

Chirp SBP(Sub-Bottom Profiler) is a marine high-resolution seismic system applied in a variety of marine geological and geophysical fields. The conventional Chirp SBP system records the positive envelope signal after real-time processing. To record the raw data preserving the polarity and phase information, we constructed the new data acquisition system, and acquired the field data in the southeastern coast of Korea using the new constructed system and the conventional Chirp SBP system simultaneously. Acoustic anomalies associated with shallow gas have been reported in KSSM(Korea Strait shelf mud) off SE Korea. We performed the correlation of raw seismic data with the estimated sweep signature, swell effect correction and deconvolution to compare the resolution of Chirp SBP sections and to enhance the features associated with shallow gas. When we compare Chirp SBP section preserving polarity and phase information with the conventional envelope section, the new section shows better continuity of the sedimentary layers and higher resolution than conventional section. A possible gas related acoustic anomaly was found on the Chirp SBP section and the piston core and KISOS(KIGAM Seafloor Observation System) data were acquired for the detailed analysis.