| 摘要: | 地下水文地質結構的空間非均質性會影響地下水的產生、流動及其相互作用。然而，僅依賴稀疏鑽孔資料的模型往往無法充分表徵這種變化。本研究利用電法與電磁法地球物理資料結合鑽孔資訊，對臺灣濁水溪沖積扇（CRAF）與衣索比亞塔納湖盆 Fogera 平原的水文地質特徵進行成像與表徵。研究共獲取 CRAF 區域 114 個 TEM（瞬變電磁）測點及 Fogera 平原 20 個 VES（垂向電測深）測點。CRAF 的 TEM 資料反演採用基於 VES 的先驗模型，而 Fogera 平原的 VES 資料反演則採用一維粒子群優化演算法。兩種方法均通過鑽孔記錄進行驗證。
在 CRAF 區域，結果顯示地表存在一薄的高電阻層，其下方為厚度約 40 m 的低電阻區。在該低電阻區之下，於 50–125 m 深度範圍內出現電阻率為 50–350 Ω·m 的高電阻層，大多數位置在更深處亦存在低電阻層。在 Fogera 平原，厚度變化為 8–40 m 的低電阻層位於中等電阻率單元（9–20 Ω·m）之上，其下約 40 m 深度處出現第二個低電阻層，而在約 70 m 以下則為高電阻區。插值後的二維剖面對鑽孔資料呈現出良好一致性。結果表明，CRAF 的結構序列為：無壓含水層—隔水層—含水層—隔水層；Fogera 平原則呈現隔水層—無壓含水層—隔水層—含水層的序列。電阻率深度切片圖及層次凝聚聚類（HAC）進一步突出這些結構的橫向變化與區域相似性。總體而言，本研究展示了 TEM 與 VES 在複雜水文地質環境成像及可持續地下水管理中的有效性。
;The spatial heterogeneity of subsurface hydrogeological structures affects the occurrence, flow, and interaction of groundwater. However, models that rely solely on sparse borehole data often do not adequately represent this variability. This study uses electrical and electromagnetic geophysical data along with borehole information to image and characterize hydrogeological features of the Choushui River Alluvial Fan (CRAF), Taiwan, and the Fogera Plain, Tana Sab Basin, Ethiopia. A total of 114 TEM soundings in the CRAF and 20 VES measurements in the Fogera plain were acquired. A VES derived a priori model was used to invert TEM data in the CRAF, and a 1-D Particle Swarm Optimization algorithm was used to invert VES data in the Fogera Plain. Both methods were validated using borehole logs. In the CRAF area, results reveal a thin resistive surface layer, which is underlain by a low-resistivity zone approximately 40 m thick. Below this zone, high-resistivity layers ranging from 50 to 370 Ohm-m are found at depths between 50 m and 125 m, with deeper low-resistivity zones present in most locations. In the Fogera plain, a low-resistivity layer varying in thickness from 8–40 m is situated above a moderately resistive unit (9–20 Ohm-m), followed by a second low-resistivity layer at approximately 40 m depth, and a high-resistivity zone beneath ~70 m. The interpolated 2D sections show a strong correlation with borehole logs. This indicates a sequence of unconfined aquifer, aquitard, aquifer, and aquitard in the CRAF, as well as a sequence of aquitard, unconfined aquifer, aquitard, and aquifer in the Fogera Plain. Depth-slice resistivity maps and Hierarchical Agglomerative Clustering (HAC) further highlight lateral variations of these structures and zone similarities. Overall, the study demonstrates the effectiveness of TEM and VES for imaging complex hydrogeological settings for sustainable groundwater management. |
