GEOLOGIC HISTORY
Constructed on the south rim of the Lerek caldera, 43 km
south of Iliboleng volcano, Iliwerung forms one of the
southern peninsulas of 85-km-long Lomblen Island, which lies
midway between Flores Island on the west and Alor Island on
the east. Craters and lava domes have formed along N-S and
NW-SE lines on the complex volcano.
Historic Activity:
- There have been 11 documented eruptions since 1870 at
vents from the summit to the submarine south flank,
generally along a N-S zone defined by craters and lava
domes.
- An eruption in Dec. 1973 began with submarine
activity and by July 1974, there were 2 small islands at
the eruption site and a third emerged in August. All have
subsequently been eroded away.
- In July 1979, about 50 million cu m of Iliwerung were
removed by a landslide. About 1/3 of this material
entered the sea, and (probably aided by additional
submarine slumping) generated a tsunami that killed
hundreds of people.
Recent Activity:
- Explosions occurred on Aug. 17 & 18, 1983 from a
submarine vent (called Hobal) south of Iliwerung.
- A submarine eruption in the Alor Strait was reported
on Sept. 16, 1993 by a Japanese cargo ship. Three
explosions, each produced a water column about 100 m
high. The Volcanological Survey of Indonesia confermed
that an eruption had occurred from the submarine Hobal
vent at Iliwerung (8.538° S, 123.592° E).
Data Sources
- Smithsonian's SEAN Bulletin (V. 8, No. 8)
- Global Volcanism Network (V. 18, No. 8 and V. 18, No.
10).
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