本研究應用直流電阻法，研究八卦台地之電性地層特性、其分布情形及探討電性地層與岩性的相關性。本研究將野外收集的 248 個地電測點資料，參考井地層柱資料，進行一維逆推處理。並在測區內完成 2 條地電阻影像剖面探測，作二維逆推處理，經解釋後獲致以下數點結論： 1.依電性地層之特性，測區可分為八大分區，三個電性地層，第一層可與紅土礫石層對比；第二層與台地礫石層對比；第三層則對比至頭嵙山層之頂部。 2.測區內沈積物的組成大都為台地礫石層，在整體岩相上差異頗大，而地層中所含岩性之顆粒度大小是造成此區域地層電阻率改變之主要原因。 3.電阻率層與井地層岩性之比對結果良好，粒度大者普遍電阻率高，而電阻率呈現上高下低的趨勢。 4.在赤水地區之2條東西向之階崖做的2條跨崖的南北向走向之RIP測線，依地層電阻率譜研判，第一層為紅土礫石層；第二層為卵礫夾砂土；第三層為粗砂夾米礫之更新世頭嵙山層。 5.測線剖面上出現之電阻不連續現象研判不是斷層作用所造成，而是河道變遷後河流下切所造成。 The electric resistivity method was used in this study to investigate the properties and distribution of the electrostratigraphic units in the Pakua terraces area. 248 vertical electric sounding data are interpreted with the method of 1-D inversion. And 2 RIP data are interpreted with the method of 2-D inversion. According the interpretative result,several conclusions were drawn as follows： 1.Depend on the subsurface electrical properties, the study area can be divided into eight region and the strata can be divided into three electric units. 2.The sediments in the whole area are mainly consisted of the terrace gravel. Thus, the change of the resistivity in the study area is more affected by the grain contented in the stratum. 3.The layer of resistivity contrast very well with the layer of well column in lithological characters. The high grain often has the high resistivity, and the trend of resistivity shows that high resistivity in the upper layer and the low resistivity in the lower layer. 4.2 RIP in Chi-shui area, According to the resistivity, the first layer was consisted of the laterite gravel; the second layer was consisted of the gravel with soil; the third layer was consisted of the Pleistocene sand with gravel. 5.The uncontinuous of resistivities at the profile was not caused by fault, it was cause by river downward erosion. The electric resistivity method was used in this study to investigate the properties and distribution of the electrostratigraphic units in the Pakua terraces area. 248 vertical electric sounding data are interpreted with the method of 1-D inversion. And 2 RIP data are interpreted with the method of 2-D inversion. According the interpretative result,several conclusions were drawn as follows： 1.Depend on the subsurface electrical properties, the study area can be divided into eight region and the strata can be divided into three electric units. 2.The sediments in the whole area are mainly consisted of the terrace gravel. Thus, the change of the resistivity in the study area is more affected by the grain contented in the stratum. 3.The layer of resistivity contrast very well with the layer of well column in lithological characters. The high grain often has the high resistivity, and the trend of resistivity shows that high resistivity in the upper layer and the low resistivity in the lower layer. 4.2 RIP in Chi-shui area, According to the resistivity, the first layer was consisted of the laterite gravel; the second layer was consisted of the gravel with soil; the third layer was consisted of the Pleistocene sand with gravel. 5.The uncontinuous of resistivities at the profile was not caused by fault, it was cause by river downward erosion.
