DSpace community: 地球物理研究所

以卡爾曼濾波與主成分分析探討GNSS時間序列中的暫態變形訊號;Investigation of Transient Deformation Signals in GNSS Time Series Using Kalman Filtering and Principal Component Analysis

Fri, 06 Mar 2026 10:29:26 GMT

title: 以卡爾曼濾波與主成分分析探討GNSS時間序列中的暫態變形訊號;Investigation of Transient Deformation Signals in GNSS Time Series Using Kalman Filtering and Principal Component Analysis abstract: GPS位移時間序列中所含的暫態訊號可以反映地表諸多變形，如震後位移、火山作用及地下水位變化等，讓我們能夠以此研究地殼變形的性質並洞察災害發生的可能性。但在此連續位移紀錄中，存在著非常多的雜訊，導致較微弱的暫態訊號因低訊噪比而較難被觀察到。本研究參考Ji and Herring (2013)所提出的方法，將FOGM (First Order Gauss-Markov)隨機過程置入原始時間序列的狀態函數中，並以卡爾曼濾波器(Kalman filter)去除序列中固定振幅的趨勢(trend)、年週期、半年週期等狀態訊號以及白雜訊(white noise)，其所得的FOGM過程即包含了序列中各狀態分量的動態變化以及色雜訊(color noise)。最後將各站各分量的FOGM進行主成份分析(principal component analysis, or PCA)，以萃取其在時間與空間中的主要共同分量。相較於色雜訊，GPS測網中顯著的共同暫態地殼變形多來自位移趨勢中低頻且振幅較高的變化，因此將預期出現在PCA前面的幾項主成份。此方法可同時降低雜訊在時間域及空間域的影響，使微弱的暫態訊號能夠更容易被檢測。我們以位於美國西部Utah州Wasatch front區域的GPS測網資料作為範例(觀測時間>10年)，分析此區域可能出現的暫態地表變形，研究結果顯示在GPS的三分量的第一主成分皆出現佔比超過60%、空間分布均勻的共模分量(Common Mode Component, CMC)，而且垂直向的共模分量與水文訊號有相當高的相關性，顯示整體垂直向的暫態訊號受水文訊號影響。次要主成分則暗示著因乾旱而造成的以大鹽湖(Great Salt Lake)為中心向外擴張之暫態變形，我們也同時提取出該因素在水平分量在大鹽湖的位移。本研究也將此方法應用在臺北盆地，分析2019~2023年因旱季與濕季造成的暫態訊號。;Transient signals in GPS displacement time series reflect a wide range of surface deformation processes, including postseismic deformation, volcanic activity, and groundwater-related loading. However, continuous GPS records are often dominated by noise, making weak transient signals difficult to detect. In this study, we adopt the method of Ji and Herring (2013) in which a First-Order Gauss–Markov (FOGM) stochastic process is incorporated into the state vector and estimated using a Kalman filter to remove deterministic components with fixed amplitudes, including linear trends, annual and semiannual signals, as well as white noise. The resulting FOGM processes capture both dynamic variations in the displacement trend and colored noise. Principal component analysis (PCA) is then applied to the FOGM processes of all stations to extract dominant common spatiotemporal modes. Significant transient crustal deformation within a GPS network is expected to be characterized by low-frequency, high-amplitude signals and therefore to appear in the leading principal components. This combined Kalman filter–PCA approach effectively suppresses noise in both the temporal and spatial domains, enhancing the detectability of weak transient deformation. We apply this method to more than 10 years of GPS observations from the Wasatch Front region, Utah, western United States. The first principal components of all three displacement components account for more than 60% of the total variance and exhibit spatially coherent common-mode component (CMCs). The vertical CMC is strongly correlated with hydrological signals, indicating that transient vertical deformation is largely driven by hydrological loading. Secondary principal components reveal drought-induced transient deformation centered on the Great Salt Lake, with corresponding horizontal displacements identified around the lake. The method is further applied to the Taipei Basin to investigate transient deformation associated with seasonal hydrological variations during 2019–2023.

從InSAR與GNSS觀測探討2016至2021年間黃石陷落火山口的地表變形;Deformation of Yellowstone Caldera from InSAR and GNSS Observations, 2016-2021

Fri, 06 Mar 2026 10:29:17 GMT

title: 從InSAR與GNSS觀測探討2016至2021年間黃石陷落火山口的地表變形;Deformation of Yellowstone Caldera from InSAR and GNSS Observations, 2016-2021 abstract: 本研究利用2016-2021年Sentinel-1衛星資料與GNSS三分量，建立黃石地區地表變形，並探討其控制變形的機制。研究首先以DInSAR觀察空間地表變化，並進一步透過MintPy建立SBAS-InSAR時間序列，搭配大氣校正、相位坡度校正及地形殘差校正，以獲得兩時段（2016-2018、2019-2021）的可靠地表位移場。GNSS與InSAR比對結果顯示，兩時段平均誤差約5-12 mm，證實InSAR時序結果具一致性。結果顯示，2016-2021年間黃石陷落火山口整體呈現緩慢下沉，而西北邊界變形呈區域性差異：2016-2018年Norris Geyser Basin（NGB）與Terrace Spring（TS）皆抬升，抬升中心位於NGB；2019-2021年NGB轉為下沉，而TS持續抬升且幅度略增，並證實TS屬於獨立變形系統。為探討變形來源，本研究採用VMOD進行非線性反演與貝葉斯取樣，結果顯示NGB可由深度約5-6 km的Mogi收縮源解釋；TS則對應深度約2-3km、半徑約10 km的Penny-shaped crack壓力源。兩者在深度與位置上皆相互獨立。綜合地震活動、地震層析成像結果的低VP/VS結構、二氧化碳通量以及地質構造背景，本研究提出黃石西北邊界的雙系統熱液模式：NGB為裂隙通暢、易釋放流體的開放系統，而TS為低滲透性區域、易封存流體的封閉系統，導致兩區呈現反向變形。不同的構造與岩性決定了兩區域的滲透性差異，是驅動近年地表變形在空間上差異的主因。本研究不僅為黃石流體與變形關聯性提供新約制，亦進一步以地表變形證據支持TS地表淺處存在二氧化碳聚集，並凸顯TS區域持續監測的必要性。 ;This study investigates surface deformation in Yellowstone between 2016 and 2021 using Sentinel-1 synthetic aperture radar (SAR) observations and three-component GNSS measurements, with the aim of characterizing surface deformation patterns and identifying the mechanisms controlling deformation. We first applied differential InSAR (DInSAR) to examine spatial deformation signals and then generated small-baseline subset (SBAS) InSAR time series using MintPy. To improve the reliability of the time series results, corrections for atmospheric delays, phase ramps, and residual topographic errors were implemented. Deformation fields were analyzed for two time intervals (2016-2018 and 2019-2021) to capture potential temporal changes. Comparison between InSAR-derived displacement and GNSS displacement projected onto the LOS direction indicates mean discrepancies of approximately 5-12 mm for both periods, suggesting that the InSAR time series results are internally consistent and robust. The results reveal that the Yellowstone caldera experienced overall gradual subsidence during 2016-2021, while deformation along the northwest caldera boundary shows strong spatial heterogeneity. During 2016-2018, both Norris Geyser Basin (NGB) and Terrace Spring (TS) exhibited uplift, with the main uplift center located near NGB. In contrast, during 2019-2021, NGB transitioned to subsidence, whereas TS continued uplifting with a slightly increased magnitude. This temporal divergence indicates that TS represents an independent deformation system rather than a peripheral response to deformation centered at NGB. To constrain the deformation sources, we performed nonlinear inversion and Bayesian sampling using the VMOD (Versatile Modeling of Deformation) framework. The results suggest that deformation at NGB can be explained by a contracting Mogi source at ~5-6 km depth. In comparison, deformation at TS is best represented by a pressurized penny-shaped crack at ~2-3 km depth with an estimated radius of ~10 km. These two sources are distinct in both depth and location, supporting the interpretation that NGB and TS are governed by mechanically independent subsurface systems. To interpret the physical origin of the modeled sources, we integrated independent constraints from seismicity patterns, low VP/VS anomalies from seismic tomography, surface CO₂ flux measurements, and geological-structural context. Together, these observations support a dual hydrothermal system model for the northwest boundary of the Yellowstone caldera. NGB is characterized as an open hydrothermal system, where well-developed fractures and high permeability facilitate fluid circulation and efficient pressure release, consistent with the observed subsidence/deflation during 2019-2021. In contrast, TS is interpreted as a closed, low-permeability system, where fluids and volatiles are more readily trapped and accumulate pressure, producing persistent uplift. The contrast in permeability controlled by lithology and structural architecture is inferred to be the primary factor driving the spatially variable deformation observed in recent years. Overall, this study provides new constraints on the coupling between subsurface fluids and surface deformation in Yellowstone, supports shallow CO₂ accumulation beneath TS inferred from deformation evidence, and highlights the importance of continued geodetic monitoring of the TS region.

應用無人機測繪重建冰河地形：分析Waldemarbreen之地形，Kaffiøyra, Svalbard;The application of UAV in reconstructing glacier terrains: Interpretation of Waldemarbreen in Kaffiøyra, Svalbard

Fri, 06 Mar 2026 10:29:04 GMT

title: 應用無人機測繪重建冰河地形：分析Waldemarbreen之地形，Kaffiøyra, Svalbard;The application of UAV in reconstructing glacier terrains: Interpretation of Waldemarbreen in Kaffiøyra, Svalbard abstract: 全球氣候暖化為當代地球科學研究之核心焦點，其中冰河退縮不僅是氣候變遷的顯著指標，更提供了探究地表動態演化的關鍵線索。本研究聚焦於北極斯瓦巴群島（Svalbard）之 Waldemar 冰河，旨在探討其退縮後新生裸露地標之地貌特徵。 Kaffiøyra 地區地質構造複雜，地層橫跨前寒武紀基盤至第三紀，並保有顯著的斷層活動遺跡，具備極高之科學研究價值。早期極區地圖多仰賴中低解析度衛星遙測，缺乏高精確度之空間資訊，且受限於大面積冰川覆蓋，歷史地形資料極為匱乏。本研究之創新與優勢在於導入無人飛行機（UAV）攝影測量技術，針對冰河退縮區進行高解析度影像採集，並透過 Agisoft Metashape 產製公分級解析度之數值地形模型（DEM）與正射影像（Orthophoto）。此高精度資料不僅能優化水文分析模型與地質詮釋，更精確建構了 2023 年 Waldemar 冰河區域之地貌現狀。本研究成果填補了台灣在極地地形測繪資料之空白，為後續冰川學與環境變遷研究提供關鍵的基礎數據庫。;Global warming has become a focal point of earth science research, and glacial retreat is one of the critical indicators of climate change. The study focuses on the post-glacial landforms of the Waldemar Glacier in Svalbard. The Kaffiøyra region of western Svalbard features a complex geological structure, spanning from Precambrian basement rocks to Tertiary formations, and evidence of tectonic faulting. Despite the scientific significance of the area, existing polar cartography often suffers from low resolution or a lack of historical data due to the extensive prior large-scale glacial coverage. To address these limitations, this research used Unmanned Aerial Vehicle (UAV) photogrammetry to survey newly exposed terrain. The research generated centimeter-scale digital elevation models (DEMs) and orthomosaics by processing aerial imagery through Agisoft Metashape. These high-resolution data can be used in precise hydrological analysis and geomorphological interpretation of the Waldemar Glacier topography in 2023. This study contributes foundational high-resolution data to Taiwan’s polar research initiatives, establishing a rigorous geographic baseline for future longitudinal studies in the Arctic.

透過反射震測法分析北桃園區域是否適合作為碳封存場址

Fri, 06 Mar 2026 10:28:44 GMT

title: 透過反射震測法分析北桃園區域是否適合作為碳封存場址 abstract: 隨著全球對減碳需求日益增加，碳捕捉與封存（Carbon Capture and Storage, CCS）技術成為實現淨零排放的重要手段之一。透過CCS技術可將工業排放的二氧化碳捕捉、壓縮並注入深層地層中進行永久封存，有效降低二氧化碳排放、減緩溫室效應。台灣雖已初步辨識出幾個潛在的封存系統，但因地質構造破碎、地震活動頻繁，封存場址的可行性、安全性與長期穩定性仍需進一步評估，以確保其在永續發展上的有效性與風險管理。本研究運用淺層反射震測技術，針對桃園北部沿海地區進行震測調查，規劃六條測線分析此區域的地下地層構造，評估其作為二氧化碳封存場址之潛力。淺層反射震測相較於傳統探油震測具有較高解析度，能有效描繪地下數百米至三公里以內的地層變化，適合作為封存場址初步篩選所使用的地球物理方法。此外，為提升地層解釋的準確性，本研究運用兩種不同震測資料處理系統：Shallow Seismic System及RadExPro Professional，在資料處理上選擇對於每個步驟較為適合的軟體進行互補分析，強化訊號品質與剖面之清晰度。經過觀察最終剖面後，可發現該區域地層近乎水平且沒有明顯之地層錯動，而目標儲集層之厚度約為900公尺，顯示該地區具有良好封存潛力。本研究之成果不僅有助於瞭解桃園沿海地下地質構造，也為未來台灣將實施的二氧化碳地質封存計畫提供實質參考。;As global decarbonization efforts intensify, Carbon Capture and Storage (CCS) technology has become one of the key approaches to achieving net-zero emissions. CCS involves capturing carbon dioxide (CO₂) emitted from industrial processes, compressing it, and injecting it into deep geological formations for long-term storage. While Taiwan has preliminarily identified several potential CO₂ storage systems, the region′s fractured geological structures and high seismic activity demand comprehensive evaluation of site feasibility, safety, and long-term stability. This study applies the Shallow Seismic Reflection Method to investigate subsurface structures in the northern coastal area of Taoyuan. Six survey lines were designed to analyze geological features and evaluate the area′s potential as a CO₂ storage site. Compared to conventional deep seismic exploration, shallow seismic reflection offers higher resolution and is suitable for mapping geological formations within a few hundred meters to two kilometers in depth—making it ideal for early-stage site screening. Additionally, the study utilizes two different seismic data processing systems—Shallow Seismic System and RadExPro Professional—to optimize each processing step through complementary analysis. The final seismic profiles reveal nearly horizontal strata with no apparent faulting and indicate a target reservoir thickness of approximately 900 meters, demonstrating favorable conditions for geological CO₂ storage.