DSpace collection: 研究計畫

臺灣地區111年地震前兆監測資料彙整及分析

Wed, 27 Jul 2022 02:46:03 GMT

title: 臺灣地區111年地震前兆監測資料彙整及分析 abstract: 九二一大地震後，經檢視全省磁力連續觀測資料發現，位於車籠埔斷層兩端的磁力站—鯉魚潭站及灣丘站，都觀測到磁力異常訊號，這些異常訊號與地震的發生有時間上的巧合。一般認為，當岩層受到應力作用而產生裂隙，地層內所含的帶磁礦物會散發在空間中，造成地磁場的變化。本計畫除了協助更新三分量地磁連續觀測網的觀測儀器外，同時也分析新建置的全省三分量地磁連續觀測網資料，以了解地磁場強度改變與地震活動的關聯性。本計畫預計發展預報品質的評估方式以及進行資訊分析工具的初步研究；後續擬開發資訊分析工具並將其應用於同時聯合地電與地磁觀測的TIP機率預報中。藉由資訊理論的應用以及基於地電、磁觀測資料之TIP預報方法的整合，我們將得以更全面的方式探討地震前兆現象，並期待能更進一步提升整體預報表現。本研究計畫將利用上述分析之長期間(1994年-2021年)電離層異常資料，研究地震前電離層異常的特性。除了時間上的異常之外，本研究同時分析電離層異常區域與震央之間的關係，建立地震前電離層異常的時空分布圖。當觀測到電離層異常時，可作為地震預警判斷之用。 ;After 921Chi-Chi earthquake, numerous magnetic anomaly signals were observed in the northern and southern parts of the Chelungpu fault, and it is coincided with the time of Chi-Chi earthquake occurred. It is generally believed that the magnetic minerals contained in the formation will be dispersed in space, causing changes in the geomagnetic field. This project analyzes the new 3-components geomagnetic observation network to understand the associated with seismicity and changed in tectonic stress. we plan to investigate methods for assessing probability forecast and develop tools for informational analysis. we plan to develop the tools of informational analysis and apply them in the integrated TIP forecasting system. With the application of informational theory and the integration of the previously developed TIP forecasting systems, we can have a better comprehension about the pre-seismic electromagnetic phenomena. By employing the above-mentioned long-term ionospheric anomaly results during 1994-2021, the purpose of this project is to study the characteristics of ionospheric anomaly, such as the temporal precursor and the relationship between the spatial anomaly and the earthquake. The ionospheric time-space anomalous distribution map will be further developed for the seismic precursor in the ionosphere.

離岸風場海域地質調查及地質環境資訊服務－高解析地層及海床地貌調查（1/4）;Marine geological survey and geo-environmental information services of offshore wind farms－High-resolution surveys of stratigraphy and seafloor geomorphology (1/4)

Wed, 27 Jul 2022 02:46:01 GMT

title: 離岸風場海域地質調查及地質環境資訊服務－高解析地層及海床地貌調查（1/4）;Marine geological survey and geo-environmental information services of offshore wind farms－High-resolution surveys of stratigraphy and seafloor geomorphology (1/4) abstract: 為達到政府2025年非核家園目標，離岸風電為其中重要綠能政策之一，而海域地質條件又關係到風機基礎穩定及維運安全。地調所本於「海洋地質調查」的業務職掌，規劃在離岸風電場址進行海洋地質環境調查，提供基礎地質環境資料，補足離岸風電地質環境資料缺口。因此，自111年起地調所推動此4年期「離岸風場海域地質調查及地質環境資訊服務 (1/4)」科技計畫，並規劃於離岸風電開發區域進行詳細地質調查及地質與環境感知系統建置。預期能建構友善綠能風電產業環境，讓離岸風機綠能產業在既有完善的地質環境下，節省細部地質調查時程與經費，加速風機建構。其中浮台式風機主要設置在水深深於50米區域，風機基樁會錨定於海床，因此海床底質及淺層地層條件對於風機安全至關重要。本團隊將參與此4年期計畫中的「高解析地層及海床地貌調查計畫」，作業重點是探測並分析風電潛能場址的海床特徵物、海床底質特性及淺部地層構造，並繳交相關探測與分析結果供海域地質資料庫建置使用。因此，本團隊規劃於111年度計畫調查區域內進行以下5項探測作業：（1）為瞭解海床下淺於500 m以上的淺部沉積層的精細地層構造，預計使用電火花震測系統來進行測線長度至少200 km以上的震測資料收集與處理，並搭配調查區域內既有震測資料作分析；（2）為瞭解海底地貌特徵及近海床淺於50 m的淺部地層特殊構造與沉積特徵，預計使用底拖聲納來進行測線長度至少200 km以上的側掃聲納與底質剖面資料收集、處理與分析，且提供海床影像探測作業站位的參考；（3）為能判釋海底特殊地形構造，預計使用船載多音束測深系統來進行面積至少300 km2的水深資料收集、處理與分析，且提供海床影像探測作業站位的參考；（4）為瞭解火成岩體、沈船和未爆彈的分布範圍，預計使用表拖磁力儀來進行測線長度至少200 km的磁力資料收集、處理與分析，且提供海床影像探測作業站位的參考；（5）為能確認海床底質特徵及分類，以及辨識海床上特徵物體性質，預計使用水下拖曳式即時攝影系統來進行測線長度至少5 km或時間5小時以上的海床影像觀測資料收集、處理與分析。 ;Offshore wind power is one of the critical renewable energy to achieve the goal of nuclear-free homeland by 2025. Offshore geological condition is extreme crucial to maintain the safety of offshore wind turbine structures. Base on the responsibility for the “Offshore geological Investment” plan, Central Geological Survey has planned to investigate the marine geological environment of the offshore wind farm field. Providing the fundamental information of geological environment can help to make up the deficiency of the offshore wind farm field geological data. Start from 2022, Central Geological Survey open the project, “Geological survey of offshore wind farms and geological environment information services (1/4)”, aims to collect the detail geological and geophysical survey and establish the environmental sensing system. The results of this project are expected to provide the friendly environment for the wind farm industry and promote the construction of the wind turbines by saving time and money for detail survey. For the deep water environment (water depth more than 50 m), the floating wind turbines anchor the construction pile into the seafloor. Therefore, it is very important to understand the seafloor geology and surficial seafloor geological condition for the security of the wind turbines. In “High resolution stratum and seabed geomorphological survey (1/4)” project, the main targets of the offshore survey are analyzing the seafloor features of the potential wind farm fields, the characteristic of the seafloor geology, the seafloor surface structures and further providing the related survey and analyzed data to build the offshore geological database. In this respect, we have suggested 5 survey operations within the survey area in 2022, including (1) To understand the detail structure in shallow strata less than 500 m depth, we plan to collect and analyze Sparker seismic reflection data for at least 200 km data length, and analyze along with the seismic reflection data in previous studies; (2) For the strata shallower than 50 m, we plan to use sub-bottom sonar to collect, process and analyze at least 200 km data length for side-scan sonar and sub-bottom profiler data to understand the detail shallow structures, sedimentary features and for the reference of seafloor image survey; (3) For the overall seafloor morphology, we plan to use on-board multi-beam echo sounder system to collect, process and analyze at least 300 km2 data and provide to the seafloor image survey for detail reference; (4) For the detail distribution of volcanic rocks, shipwreck and unexploded bomb, we plan to use surface-towed marine magnetometer to collect, process and analyze at least 200 km data length and provide to the seafloor image survey for detail reference; (5) For understanding the seafloor characteristics and classifying seafloor features, we plan to use the deep-towed vehicle Abyss Twisted-pair Imaging System to collect, process and analyze seafloor video footage for at least 5 km along-track length or 5 hours recording duration.

109年度地震資料之分析應用

Mon, 13 Jan 2020 06:22:15 GMT

title: 109年度地震資料之分析應用 abstract: 完整的場址效應包括線性及非線性行為下的不同特性，多數情況下場址效應接近線性的放大特性，但在軟弱地盤、高震度情況下，高頻地震波的非線性放大特性就會變得顯著。本研究擬分析陸地及海底的非線性場址放大效應，在陸地上，利用氣象局設置的地表—井下地震站進行分析，近年來該地震網已收集到數個大規模的強震資料，並有研究分析其淺層剪力波速度構造與場址參數，這些資訊可以用來分析井下傳遞到地表的震波放大特性之變化；在海底，因強震和鑽井資料遠比陸地稀少，故以往少有海底強震特性的研究，而近年來氣象局在宜蘭外海建置海纜強震儀，距離琉球隱沒帶很近，可望有數筆高震度資料可進行分析，或許能對海底的場址效應有初步的了解。 ;Seismic site effect should consist of linear and nonlinear behaviors. Seismic waves are usually amplified linearly in most cases, but high frequency seismic waves could express nonlinear amplifications under high intensity especially at soft soils. This study will analyze nonlinear site amplification for both inland and offshore sites. For the inland sites, we would like to use the Surface-Downhole stations for the analysis because several large magnitude earthquakes have been recorded by the network and the shallow S-wave velocity profiles as well as the site parameters are available from recent studies. We are able to analyze the variation of seismic amplifications from downhole to surface using the data and information. For the offshore sites, there was no strong motion studies due to lock of data. The CWB has installed instruments on offshore Ilan. The locations are close to the Ryukyu subduction zone so several high intensity ground motion records may be available for our analysis to understand site effect at ocean bottom.

利用強地動資料層析嘉南平原速度構造;Using strong motion data to invert velocity structure in Chianan plain

Fri, 11 Sep 2015 07:08:03 GMT

title: 利用強地動資料層析嘉南平原速度構造;Using strong motion data to invert velocity structure in Chianan plain abstract: 嘉南平原位處地震活動帶，且人口稠密屬地震災害的高潛勢區。本研究計劃分析嘉南平原過去的地震活動特性，並利用氣象局的強地動觀測網在此的高密度的空間分布，將過去累積觀測的地震波到時，來逆推嘉南平原地區高解析的三維速度構造。地震活動方面，我們將採用氣象局的地震目錄分析此區地震的空間分布，輔以GCMT的斷層面解，探討嘉南平原的應力狀態及其與地體構造的關係。速度構造方面，方法延續我們前兩年逆推宜蘭及花東地區速度構造所使用的FMTOMO程式，已熟稔該程式的操作。結果將可瞭解嘉南平原地震分布還有應力狀態與速度構造之間的相關，並預測此區未來可能的地震風險，速度構造同時可對地熱潛能作一評估。;Chianan plain locate in seismic active Southwest Taiwan. The dense population and potential to generate large and shallow earthquake make this region a potentially hazardous area. In this proposal, we plan to analyze the characteristic of seismic activity in Chianan plain and conduct a tomographic study to invert for high resolution crustal velocity structures of the area. Seismicity from Central Weather Bureau catalogue and fault plane solution from GCMT can be used to study the state of stress and its relations to tectonics in the Chianan plain. We will apply FMTOMO (Rawlinson et al., 2006) to conduct the inversion in two phases based on P and S arrival times recorded by strong motion stations in the area deployed by Central Weather Bureau over the past decade or so. The resulting velocity structures can be used to correlate with the seismic behaviors, and to give an assessment of geothermal potential. We expect that fulfillment of the project will significantly help understand the seismotectonics of the Chianan plain for a better prediction on potential zones of future earthquakes for hazard mitigation.;研究期間：10403~10412