Hydroacoustic ray theory‐based modeling of T wave propagation in the deep ocean basin offshore eastern Taiwan

• Published in: Geophysical research letters Vol. 44; no. 10; pp. 4799 - 4805
• Main Authors: Chen, Chin‐Wu, Huang, Chen‐Fen, Lin, Chien‐Wen, Kuo, Ban‐Yuan
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28.05.2017
• Subjects: Acoustic propagation; Acoustics; Basins; Computer simulation; Detection; Energy; Huatung Basin; hydroacoustic ray theory; Modelling; Ocean basins; Ocean bottom; Ocean floor; Ocean models; ocean‐bottom seismometer; Offshore; Propagation; Scattering; Sediment; Seismographs; Seismometers; Sofar; Sound; Sound fixing and ranging; Sound propagation; Sound velocity; T waves; Wave propagation; Taiwan
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2017GL073516

T waves are conventionally defined as seismically generated acoustic energy propagating horizontally over long distances within the minimum sound speed layer in the ocean (SOFAR axis minimum). However, T waves have also been observed by ocean‐bottom seismometers in ocean basins at depths greater than the SOFAR axis minimum. Previously, nongeometrical processes, such as local scattering at rough seafloor and water‐sediment interface coupling, have been proposed as possible mechanisms for deep seafloor detection of T waves. Here we employ a new T wave modeling approach based on hydroacoustic ray theory to demonstrate that seismoacoustic energy can propagate to reach deep seafloor, previously considered as shadow zone of acoustic propagation. Our new hydroacoustic simulations explain well the observations of T waves on ocean‐bottom seismometers at deep ocean basins east of Taiwan and shed new light on the mechanism for deep ocean T wave propagation. Key Points T waves are detected by an OBS deployed at a water depth of 4726 m in the Huatung Basin offshore eastern Taiwan Hydroacoustic ray model is implemented to simulate T wave propagation in the deep ocean Acoustic energy propagating out of the SOFAR axis of minimum sound speed can explain the OBS detection of T waves in Taiwan