Part of the detection and monitoring of seismic events will be provided by low-frequency hydrophones (2 Hz to 20 KHz) that are well suited to detect the hydroacoustic tertiary phase of T waves of oceanic earthquakes. These sensors also detect solid-earth P waves from regional and teleseismic earthquakes. Coupled with the Ocean Bottom Seismometers, the low-frequency hydrophones will increase our ability to detect offshore earthquakes in real-time, determine their magnitude, and enable better location accuracy.
The Low Frequency Broadband Acoustic Receivers are manufactured by HTI, model 90-U. HYDLFA305 is located in the Central Caldera and is coupled with broadband seismometer OBSBBA301; both instruments are connected to the MJ03F J-box by a 50 m-long extension cable. The Central Caldera subnet also hosts a Bottom Pressure and Tilt meter.