1. Seismic activity recorded by a single OBS/H near the active Longqi hydrothermal vent at the ultraslow spreading Southwest Indian Ridge (49°39′ E).
- Author
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Liu, Yunlong, Tao, Chunhui, Liu, Cai, Qiu, Lei, Schlindwein, Vera, Zhang, Haijiang, Tian, You, and Wang, Hanchuang
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HYDROTHERMAL vents , *MID-ocean ridges , *OCEAN bottom , *PILOT projects , *SEISMOMETERS , *VOLCANOES - Abstract
In this paper, we describe the results of a first pilot experiment of passive seismic monitoring near the active Longqi hydrothermal vent at the Southwest Indian Ridge during Chinese cruise DY115-30. During 102-day experiment, we recorded over 2,000 seismic events on a single ocean bottom seismometer with hydrophone close to the hydrothermal field. We classified these events into the following three classes based on their time–frequency characteristics: (1) volcano tectonic microearthquakes (VTMs); (2) regional earthquakes; (3) short-duration events (SDEs). We preliminarily located the 1,277 VTMs using a single-station location method. Our results revealed hypocenters primarily beneath the axial valley ridge which is about 10 km away from hydrothermal vent and extending to the upper mantle at a depth of 15 km. Two discrete swarms of VTMs occurred during our survey period. The SDEs show a complex frequency characteristics ascribed to clusters of monochromatic waves around different frequencies. This suggests that SDEs result from combination of harmonic waves resonating in fluid-filled pipes and cracks. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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