| Country: | South Korea | ||
| Subregion Name: | Korea | ||
| Volcano Number: | 1006-04- | ||
| Volcano Type: | Shield volcano | ||
| Volcano Status: | Historical | ||
| Last Known Eruption: | 1007 | ||
| Summit Elevation: | 1950 m | 6,398 feet | |
| Latitude: | 33.37°N | 33°22'0"N | |
| Longitude: | 126.53°E | 126°32'0"E | |
| The massive Halla shield volcano forms much of the 40 x 80 km Cheju (Jeju) Island, which lies 90 km south of the Korean Peninsula. Eruptions during the Pliocene and Pleistocene built a lava plateau above the roughly 100-m-deep continental shelf on which the basaltic-to-trachytic Halla shield volcano was constructed. A 400-m-wide crater truncates the 1950-m-high summit. About 360 late-Pleistocene and Holocene basaltic parasitic cones dotting the flanks of the low-angle volcano were erupted primarily along the long axis of the ENE-WSW-trending island. Most of these are scoria cones, but about 20 along the coast of the island or offshore are Pleistocene-to-Holocene tuff rings and tuff cones, and lava domes also occur. Flank eruptions continued into historical time, with the final two taking place during the 11th century. | |||