Volcanic landscapes in the active weathering environment
Penghu islands possess various volcanic landscapes which are the oldest one in Taiwan and their volcanic landscapes are not much distorted by ad hoc tectonic shifts. The formation of Penghu basalts represents the event that crustal deformation occurred in the East China Sea and the South China Sea between 17.4 million and 8.2 million years ago with successive volcanic eruptions. Different levels of basalt lava flow erupted onto the surface through different geologic time periods and then formed today’s surface structures and landforms in Penghu. The oldest rock strata of the Penghu region are located in Huayu, farthest to the west in Penghu. Huayu is the only islet composed of andesite lava flow (Volcanic Island Arc type). The rest of Penghu islands are composed of basalt lava flow. During the Quaternary period, besides on the affection of sea erosion, the laterite layer was developed in the surface horizon of soils followed with the crustal uplift and subsidence. Notably, in Penghu, there are no high mountains to withstand wind. Thus Penghu islands have a high frequency of sand-laden wind blowing and bad weather. That combination of volcano tectonic processes and weathering by wind and ocean waves forms attractive diversity in landforms and landscapes of Penghu. Consequently, except for the common cape bays, we can also see wave-erosion platform, wave-erosion cliff, wave-erosion cavity, sandy coast and rocky coast landforms along the coast area.
Stone pagoda: The livelihoods of most islanders depend highly on fisheries. In order to survive in this difficult environment, a special talisman – stone pagoda (one type of protective deities) is situated in the surroundings of the village. It is believed to quiet down the wind and ward off the ghost. Stone pagoda is one of the largest sized talismans in Taiwan and one of the most powerful talismans believed by the villagers.
Stone weirs: The stone weirs were made of coral, basalt stones and rocks show the traditional wisdom of capitalizing on the shadow tidal flats to harvest fish from the sea. Stone weirs must be built in the broad intertidal zone with strong waves and large tidal range, and in the area where the stone material can be easily obtained. Nowsaday, those fishing stone weir architectures become unique and valuable heritages attracting tourists. The famous Double-Heart stone weir in Cimei islet, Couple stone weir in Erkan village are all typical examples.
In the wider range, the densely distributed stone weirs along the coast of Jibeiyu demonstrate how significant the economy of the islet depended on these structures in historic times. The stone weirs presents a close relationship between the people’s daily and the marine life, and shows the close social inter-relationships among village people.
Kuei-bi-shan in North Village, Husi, Penghu is another typical example. When the tide is low, the area between Chi-yu and main islet reveals a narrow strip of intrusion dyke which local people use as a tidal flat to collect marine resources for family use. It is also an ideal place for tourists to experience the tidal differences and observe marine creatures.
Hsiao-men-yu is best known for its eroded coast and cliff, and biostromal limestone or Coquina. The Whale Cave is one unique sea arch, where we can observe volcanic lava stacked in different periods and palaeo-soil layers between eruptions stuck in the middle.
Traditional villages: There are numerous traditional villages of early immigrants in Penghu reflecting different cultural factors and the long history of Penghu. Those old villages which are well kept and reserved contribute to shape the unique view of Penghu such as the ancient lao-gu stone constructions and houses, special temples and camps, towers to calm wind. There are some famous villages like Central Street in Magong Erkan, or two-can village in Xiyu Township.
Beehive farmland and crop house: Facing with the strong northeast wind, every single lap-go stone or basalt rock was used to build the wind proof wall. Agricultures for dry crop usually scatter around their houses and are therefore called "crop house". And all these agricultures are so close that the whole land looks like a beehive with those walls and then people call it bee hive farmland.