碩士 / 國立臺灣科技大學 / 電子工程系 / 99 / Taiwan island is located on the junction of the Eurasian plate. There is high ratio of earthquakes occurring in the sea area around it. However, Institute of Earth Sciences, Academia Sinica points out that the earthquake observation points surrounding Taiwan sea area is only one-tenth of the land’s. It makes the earthquake monitoring data sparse. Therefore, in order to clearly grasp and measure undersea earthquake, domestic research team is positive to develop OBS (Ocean Bottom Seismometer).
The OBS is a self contained data-acquisition system which free falls to the ocean floor and records seismic data generated by earthquakes. It can be retrieved from undersea after completing task and reused. The function is the same with the Seismometer on land. But, because the placement location is up to the depth of six to seven thousand meters of seabed, it must be protected by pressure shell. Moreover, the seabed is undulating so that OBS has to equip with balance ring to maintain the level. When it is located on the seabed, the system must sense the earthquake wave and record it. Each process has been performed automatically. When finishing the work, it floats from the seabed by itself and generated the signal to request to be retrieved.
In order to implement it, a recording system board with low power microprocessor ARM7 core has been realized. Also, a SEASCAN TIMEBASE Module is integrated into the system to record the start time and end time. Finally we can store the data to SD CARD. The total power consumption is 2 Watt and the time shift is only 16ms in half year. With regard to the device retrieval, a PC board with 8 bit CPU AVR core is carried out to receive the recall signals, control the motor for freeing OBS and send GPS positioning information by radio. It makes OBS retrievable.
The experiment result shows that the recording system can store data to SD CARD successfully. We successfully place five pieces of OBS around Green Island. The deepest depth is up to 3000 meters. After two and half month, the device retrieval system can receive signals to open motor and retrieve OBS successfully.
| Identifer | oai:union.ndltd.org:TW/099NTUS5428155 |
| Date | January 2011 |
| Creators | Wen-Chieh Cheng, 鄭文傑 |
| Contributors | Mon-Chau Shie, 許孟超 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 61 |
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