Page 196 - Volcano and Geothermal Tourism

Jeju: South Korea’s Premier Island Geotourism Destination 173

Seongsan Ilchulbong tuff cone Sanbangsan lava dome
Seongsan Ilchulbong Tuff Cone (Seongsan), also Sanbangsan is a gigantic lava dome formed by the
known as ‘Sunrise Peak’, is one of the best known slow effusion of highly viscous lava. It is located in
volcanic cones on Jeju Island. Unlike the other the south-western margin of Jeju Island, rising
volcanic cones found on Jeju, Seongsan formed by 395m above sea level (Figure 11.4). A lava dome
the explosive interaction of hot magma and results from the slow effusion of felsic, commonly
seawater upon a shallow seabed about five thousand very viscous lava from a volcanic vent. The
years ago (Sohn and Chough, 1992). The hydro- viscosity of the lava prevents it from flowing far
magmatic eruption, similar to that of Surtsey in from the vent, causing it to solidify quickly and
Iceland in 1963 (Thorarinsson, 1967), produced a creating a circular dome-like shape. The lava dome
steep-sided cone of tephra, a pile of air-fall is one of the oldest rock formations on Jeju Island,
material thrown into the air by a volcanic eruption being about 800,000 years old (Won et al, 1986).
and called a ‘tuff cone’. This 182m high tuff cone Vertical columnar joints, about 2m in width and
dominates the eastern seaboard of Jeju Island like more than 100m in height are well exposed on
a huge ancient castle (Figure 11.3), with its bowl- the southern cliff wall of the lava dome. Beneath
like crater and excellent geological exposures, thus the jointed lava occurs a thick layer of volcanic
revealing the birth and growth history of an breccia composed of angular fragments of lava.
emergent volcano erupted from a shallow seabed The breccia suggests that the dome experienced
(Sohn and Chough, 1992). Seongsan is probably explosive eruptions or dome collapse during its
the best example of hydromagmatic volcanoes that growth due to build-up of gas pressure. The
has the typical morphology of a tuff cone, shows dome-forming lava and breccia overlies the basaltic
diverse internal structures along the sea cliff tuff of Yongmeori, the oldest rock formation on
exposures, and boasts outstanding beauty (IUCN, Jeju Island (Sohn, 1995) and indicates that it was
2007). It is a cherished landmark which attracts the site of the first lava eruption. A roadcut
numerous tourists to view it at dawn and dusk as between the lava dome and Yongmeori shows
it catches sunrise and sunset light from its rim. clearly the relationship between these two rock
Seongsan is the most heavily visited geotourism formations.
sites on Jeju Island (UNDP-WCMC, 2007). Sanbangsan contains the Sanbang Cave Buddhist
Temple on the middle of its southern slope which
Sangumburi crater is a tourist destination in itself. The steep but well
Sangumburi, meaning ‘hole-in-the-ground’, is a maintained steps allow visitors to reach the cave
peculiar volcanic crater distinguished from the where Buddhist monks still worship. Visitor infra-
other volcanic cones and craters of Jeju Island. The structure includes eating opportunities, souvenir
crater rim of Sangumburi is 31m higher than the shops, rest rooms and parking. Large numbers of
surroundings; the rim-to-rim width is 635m; the visitors experience this site.
diameter of the crater floor is about 300m; the
height from the crater floor to the rim is 132m. Yongmeori coast
The crater is a pit crater formed by sinking or Yongmeori, meaning ‘dragonhead’, forms a small
collapse of the surface surrounding a vent that promontory to the south of the Sanbangsan lava
exuded lava flows. Sangumburi may have been a dome. The overall geologic structures suggest
small shield volcano before the collapse. Yongmeori is a remnant of a tuff ring, which is a
Sangumburi is a geotourism landmark containing kind of hydromagmatic volcano with a relatively
a variety of visitor infrastructure including rest large crater compared with its height, deposited
rooms, souvenir shops, information centre, a mostly from pyroclastic surges and debris flows
modest food kiosk and well developed pathways that were generated by either remobilization of
and overlooks. In autumn, the crater is also wet tephra or by expulsion of wet vent-filling
surrounded by pampas grass, creating photogenic slurry of tephra (Sohn, 1995). A recent study
landscapes. suggests that the tuff ring has a rather complex

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