台灣位於歐亞板塊交界帶，台灣的地震有很高的比率是發生在海域，但是，中央研究院地球科學研究所指出台灣周邊海域的地震觀測點，卻只有陸地的十分之一，使得海域地震監測資料非常的稀少，因此，為了清楚掌握、測量海底地震，國內研究團隊積極的開發海底地震儀。

「海底地震儀」是一種可以自由置放於海床上以接收震波，工作完成後可以將儀器回收並重複使用的裝置。它的作用和陸地上使用的地震儀相同，但因為要放置在深度有時達六、七千公尺的海床，所以必須有耐壓外殼保護。海床地形有時起伏不平，故儀器內受波器的裝置要利用平衡環，使它在不太劇烈的傾斜地形還得以維持水平。而且，當它坐落於海床運作之時，必須自成獨立體系，既能感受震波，又能記錄它，而且知道什麼時候執行什麼工作。當工作結束，它又能自行脫離海床，浮上水面，並發出信號要求回收。

為了達到記錄資料的目的，本論文以低功率微處理器ARM7為核心，做出一塊地震波資料記錄系統板，搭配SEASCAN TIMEBASE模組來記錄資料的起始時間與結束時間，最後將資料儲存在SD CARD上，全部整合起來總共消耗功率2W，時間的飄移半年僅誤差16ms。在釋放裝置方面，以8 bit CPU AVR為核心做出一塊可以接收回收信號，控制馬達釋放重物，之後透過無線電波將GPS定位資料傳送出去，使海底地震儀可以正常的回收。

實驗結果顯示，本系統可以成功的將資料記錄到SD CARD上，於外海中成功的在綠島周圍置放5顆OBS，深度最深達3000米，經過2個月半，釋放裝置可以成功的接收信號，將馬達掛著的重物釋放開，成功的回收海底地震儀。

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.

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