| Project Duration | 2014-07-31 ~ 2014-11-29 |
|---|---|
| Research Title | Investigation of Potential Geological Hazard Areas on Xiji Islet |
| Contracted Organization | Juhe Engineering Consultants Co., Ltd. |
| Principal Investigator | Huang Min-Lang |
| Project Participants | Liu Feng-Rong, Yi De-Cheng, Guo Feng-Hao, Cong Jin-Hua |
| Keywords | Geological hazard map, Penghu Formation – basalt facies, steep cliffs |
| Abstract | This project, titled “Investigation of Potential Geological Hazard Areas on Xiji Islet,” aimed to identify potential geological hazard zones and their areas of influence through field investigation and analysis, and to establish classifications of different types of potential geological hazards to serve as a basis for future planning and decision-making. The strata of Xiji Islet can be classified according to lithology into the Penghu Formation – basalt facies (Ph-b), Penghu Formation – basaltic pyroclastic and lava flow facies (Ph-tb), Penghu Formation – sedimentary facies (Ph-s), Penghu Formation – volcanic tuff breccia facies (Ph-t), and modern coastal deposits (a). The island’s weathered soil layer mainly consists of red soil distributed on the northern terrace and stony soil on the southern terrace. Groundwater levels are higher near the northern terrace and gradually decrease toward the south. Results of the geological hazard assessment indicate a landslide hazard on the central western portion of the northern steep slope. Steep cliff landforms with relatively high risk are commonly found along the northern, northwestern, and northeastern island margins. In addition, the reef areas surrounding the island are subject to coastal erosion. It is recommended that residents of Dongji Islet be invited to serve as volunteers to conduct inspections after heavy rainfall or after the lifting of land typhoon warnings. Among the terrestrial scenic sites planned under the “Geological Resource Interpretation Planning and Guidebook Production for the Southern Four Islands of Penghu,” three sites are classified as high-risk areas and two as low-risk areas, all associated with steep cliff hazards. Since these scenic points are easily accessible, it is recommended that recreational activities be conducted in groups and that safety awareness be strengthened through visitor education. Xiji Islet possesses rich world-class ecological, geological, and geomorphological landscapes. It is recommended that residents and volunteers from Dongji Islet be trained as professional guides to accompany visitors when landing on the island. In addition to providing ecological and geological interpretation, such guidance would enhance visitor safety and help preserve Xiji Islet’s outstanding natural heritage. |
2014, Geological hazard map, Steep cliffs, Penghu Formation – basalt facies