Kueishantao

Kueishantao (Turtle Island) is Taiwan's youngest active volcanic island and one of the primary targets of the Taiwan Volcano Observatory (TVO). Located approximately 10 km off the northeastern coast of Taiwan near Yilan, the island preserves remarkable volcanic landforms and remains an important site for volcanic and hydrothermal research.

Background

Kueishantao is composed primarily of andesitic lava flows and pyroclastic deposits. The island is characterized by two volcanic centers, commonly known as the "Turtle Head" and the "Turtle Shell," each containing a volcanic crater. The highest point reaches approximately 398 m above sea level, while the observation platform at the summit, known as "401 Highland," provides panoramic views of the island and surrounding ocean.

Volcanic Activity

Kueishantao remains volcanically active and exhibits a variety of geophysical and hydrothermal phenomena. Seismic monitoring detects approximately 600–800 microearthquakes each month, indicating persistent subsurface activity. Geophysical studies suggest that the underlying magma reservoir may be substantially larger than that beneath the Tatun Volcano Group.

The island is also surrounded by submarine fumaroles and hydrothermal vents that release volcanic gases into the coastal waters. These emissions produce the well-known "Milky Sea" phenomenon, in which sulfur-rich particles suspended in seawater create a distinctive milky-white appearance. In recent years, renewed fumarolic activity has also been observed near the Turtle Head area.

TVO Monitoring on Kueishantao

TVO maintains a dedicated monitoring network on Kueishantao to track volcanic activity and assess potential hazards. The monitoring system includes five seismic stations distributed across the island, together with GNSS receivers, ground-temperature sensors, and other geophysical instruments. These observations provide valuable information on seismicity, deformation, and hydrothermal activity, contributing to the long-term monitoring of Taiwan's active volcanic systems.

Kueishantao

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Kueishantao

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Kueishantao

Background

Volcanic Activity

TVO Monitoring on Kueishantao

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