Lamongan

SUMMARY:

Type: composite
Activity: active
Last Eruption: 1953 AD
Rock Type: ?
Eruptive Volume: ? cu km
Location Map from Xerox PARC
Latitude: 8.00 S
Longitude: 113.34 E

GEOLOGIC HISTORY

Lamongan, a small stratovolcano located between the massive Tengger and Iyang-Argapura volcanoes, is surrounded by numerous maars and cinder cones. The currently active cone has been constructed 650 m to the SW of Gunung Tarub, the volcano's high point. As many as 27 maars with diameters from 150 to 700 m, many containing crater lakes, surround the volcano, along with 37 cinder cones. It is notable that the maars on the western slope of Lamongan all occur at elevations below the historic eruption vents, suggesting that the position of the groundwater table controls the eruptive style of Lamongan. Eruptions from above 400 m altitude form fissure vents and cinder cones which pose little threat to the local inhabitants. Activity from vents below 400 m may give rise to explosive, maar-forming eruptions.

Historic Activity:

• Lamongan was quite active during the 19th century with 40 eruptions, including more than a dozen that produced lava flows. Most were from vents located on the western slope above about 400 m altitude.

Recent Activity:

• Seismic swarm with ground breakage during Oct. 1985. The 1985 activity is in the same general area as two seismic swarms that occurred in 1925/25 and in 1978.

Data Sources

• Smithsonian's SEAN Bulletin (V. 10, No. 10 to V. 13, No. 2).

ADDITIONAL INFORMATION

• Link to Global Volcanism Network's Lamongan Information

Last Update: 2/27/00