Improvement of earthquake locations with the Marine Cable Hosted Observatory (MACHO) offshore NE Taiwan

Hsiao, Nai Chi; Lin, Tzu Wei; Hsu, Shu Kun; Kuo, Kai Wei; Shin, Tzay Chyn; Leu, Peih Lin

doi:10.1007/s11001-013-9207-3

Cited by 25 publications

(19 citation statements)

References 14 publications

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“…This estimation infers that the fundamental frequency of the marine sediments is mainly controlled by the unsolidified sediments located on the top of the seafloor. To examine this assumption, we calculated the H/V ratios based on the data recorded by the cable-based ocean bottom seismographic observatory, named "Marine Cable Hosted Observatory" (MACHO) (Hsiao et al 2014). The installed instruments of the observatory include a broadband seismometer (EOS1), which is fixed to the seafloor and buried in the marine sediments.…”

Section: The Origin Of the Fundamental Frequencymentioning

confidence: 99%

Seismic site response of submarine slope offshore southwestern Taiwan

Lin¹,

Chen²,

Su³

et al. 2018

Terr. Atmos. Ocean. Sci.

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Widely distributed Bottom-Simulating Reflectors (BSRs) have been observed in the area offshore of southwestern Taiwan where the active accretionary complex meets with the passive China continental margin. In order to clarify the link between seismic site response and sedimentary properties of submarine slope, we evaluate the response of seafloor sediments in regard to passive dynamic loads. The local site effect produced by shallow marine sediments was characterized by estimating the horizontal-to-vertical (H/V) spectral ratios of data recorded by the short-period Ocean Bottom Seismometers (OBSs). The results show that the maximal H/V ratios appeared in the range of 3.66 -9.28 Hz, suggesting that the fundamental frequency is dominated by the effect related to the very shallow sediments. For most stations, the H/V ratios estimated based on the earthquakes and noise records were characterized by different patterns. Relatively broad H/V pattern was obtained when the signals were extracted from earthquakes. This phenomenon may be related to soil nonlinearity when a stronger motion applies. In comparison with the available geological structures and bulk density distribution obtained from coring experiments, we found a relatively higher fundamental frequency of about 8 -9 Hz for the more rigid material, such as mud diapir and folding axes. For most of the area along the slope, the fundamental frequency shows a relatively low value, about 6 -8 Hz. Finally, when a site is characterized by thick or lowest bulk density sedimentary layer, we observed a fundamental frequency lower than 5 Hz, which is the lowest in our assessment.

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Section: The Origin Of the Fundamental Frequencymentioning

confidence: 99%

Seismic site response of submarine slope offshore southwestern Taiwan

Lin¹,

Chen²,

Su³

et al. 2018

Terr. Atmos. Ocean. Sci.

Self Cite

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“…[] and Hsiao et al . [], and the data selection and analysis procedure were fully documented in Kuo et al . [].…”

Section: Datamentioning

confidence: 99%

Faulting and hydration of the upper crust of the SW Okinawa Trough during continental rifting: Evidence from seafloor compliance inversion

Kuo

Crawford

Webb

et al. 2015

Geophysical Research Letters

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The elastic response of seafloor to ocean gravity wave loading, or seafloor compliance, provides a constraint on the elastic properties of the crust. We measured seafloor compliance at three ocean bottom seismometer (OBS) sites around Taiwan—two in the southwestern (SW) Okinawa Trough and one on the Ryukyu arc—and performed inversion for crustal structures beneath them. Models best fitting the data demonstrate a decrease in upper crustal shear velocity and an increase in the compressional/shear velocity ratio from the arc site to the trough sites with increasing amount of back‐arc extension. This variation suggests that the upper continental crust is highly faulted and hydrated during rifting of the Eurasian lithosphere.

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“…Due to the merit feature of shunt fault tolerance, CC mode observatories are widely adopted at scenarios requiring uninterrupted observation even with fault presence [5]. Existing CC observatories systems, including the Hawaii Undersea Geo-Observatory (HUGO) [6], the Hawaii-2 Observatory (H2O) [7,8], ALOHA Cabled Observatory (ACO) [9], the Development of Dense Ocean-floor Network System for Earthquakes and Tsunamis (DONET) [10,11], DONET2 [12,13], the Marine Cable Hosted Observatory (MACHO) [14], the Japan Trench Earthquake and Tsunami Monitoring Network Project (S-net Project) [15][16][17], etc., are all powered by CC mode and mainly used for long term observation around unstable geology seismic areas.…”

Section: Introductionmentioning

confidence: 99%

Reconfigurable Power Converter for Constant Current Underwater Observatory

et al. 2020

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A constant current (CC) underwater observatory employing the shunt method to provide constant voltage (CV) power for external loads is favored in occasions where shunt-fault tolerance is required. However, low efficiency of CC to CV conversion with the shunt method limits its application, especially in scenarios of varying loads. In this paper, a highly reliable and stable CC/CV converter with better efficiency is introduced based on the proposed novel active soft bypass (ASB) technology and the proposed novel priority-based power management strategy (PPMS). The ASB technology is a method that employs switches and a special control sequence which greatly depresses the large voltage transient presenting on the input side when trying hard bypass redundant modules, and the PPMS makes the system easy to monitor and ensures the absolute reliability of ASB technology. The theoretical study of this novel reconfigurable CC/CV converter and validation experiments on a prototype are carried out, with results showing great improvement in the performance. In addition, the proposed reconfigurable power converter is applied to a coastal observatory in the East China Sea.

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Improvement of earthquake locations with the Marine Cable Hosted Observatory (MACHO) offshore NE Taiwan

Cited by 25 publications

References 14 publications

Seismic site response of submarine slope offshore southwestern Taiwan

Seismic site response of submarine slope offshore southwestern Taiwan

Faulting and hydration of the upper crust of the SW Okinawa Trough during continental rifting: Evidence from seafloor compliance inversion

Reconfigurable Power Converter for Constant Current Underwater Observatory

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