Umboi

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 5.589°S
  • 147.875°E

  • 1548 m
    5077 ft

  • 251060
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

Most Recent Bulletin Report: September 1985 (SEAN 10:09)


Seismicity; subsidence in flank thermal area

"Following damaging earthquakes and changes at a thermal area on Umboi Island during August, local people were concerned about possible volcanic activity. A brief visit was made to Umboi by R. W. Johnson (Bureau of Mineral Resources, Canberra) on 5 September. He reported no signs of imminent volcanic threat but recommended that an officer from Rabaul Volcano Observatory (RVO) visit Umboi for further investigations.

"On 12 September, inspection of the thermal area on the W flank of Talo volcano (on the W side of Umboi Island) indicated that no increase in temperature had occurred. However, local subsidence had taken place. This was probably due to strong shaking of the ground during the strongest earthquake on 19 August.

"Nine local earthquakes were recorded 11-14 September, two reportedly felt. These earthquakes are probably local to Umboi Island, but it is uncertain whether they are directly related to the volcano. Seismic records indicate that earthquakes were continuing at a low level in mid-September."

Information Contacts: J. Mori, RVO.

The Global Volcanism Program has no Weekly Reports available for Umboi.

Index of Bulletin Reports


Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

09/1985 (SEAN 10:09) Seismicity; subsidence in flank thermal area




Bulletin Reports

All information contained in these reports is preliminary and subject to change.


09/1985 (SEAN 10:09) Seismicity; subsidence in flank thermal area

"Following damaging earthquakes and changes at a thermal area on Umboi Island during August, local people were concerned about possible volcanic activity. A brief visit was made to Umboi by R. W. Johnson (Bureau of Mineral Resources, Canberra) on 5 September. He reported no signs of imminent volcanic threat but recommended that an officer from Rabaul Volcano Observatory (RVO) visit Umboi for further investigations.

"On 12 September, inspection of the thermal area on the W flank of Talo volcano (on the W side of Umboi Island) indicated that no increase in temperature had occurred. However, local subsidence had taken place. This was probably due to strong shaking of the ground during the strongest earthquake on 19 August.

"Nine local earthquakes were recorded 11-14 September, two reportedly felt. These earthquakes are probably local to Umboi Island, but it is uncertain whether they are directly related to the volcano. Seismic records indicate that earthquakes were continuing at a low level in mid-September."

Information Contacts: J. Mori, RVO.
Download or Cite this Report

Umboi Island, 50 km in its longest dimension, is the largest of the volcanic islands off the north coast of New Guinea. Dominantly basaltic-andesitic Umboi is comprised of several coalescing stratovolcanoes that are cut by a large 13 x 17 km caldera whose walls rise up to 1 km above its floor. The caldera is widely breached to the sea on the NE side and contains three youthful post-caldera cones with summit crater lakes, Talo, Soal, and Barik. The largest of these cones, 1494-m-high Talo, displays several thermal areas and has satellitic cones on its flanks. No historical eruptions have been reported at Umboi, but activity of the post-caldera cones is thought to have continued until the last few hundred years (Johnson et al., 1972).

The Global Volcanism Program is not aware of any Holocene eruptions from Umboi. If this volcano has had large eruptions (VEI >= 4) prior to 10,000 years ago, information might be found on the Umboi page in the LaMEVE (Large Magnitude Explosive Volcanic Eruptions) database, a part of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.


Synonyms

Rooke Island | West Umboi Island | Ruk Island | Siassi Island

Cones

Feature Name Feature Type Elevation Latitude Longitude
Barik Stratovolcano 1287 m 5° 33' 0" S 147° 53' 0" E
Soal Stratovolcano 1320 m 5° 34' 0" S 147° 55' 0" E
Talo Stratovolcano 1454 m 5° 35' 20" S 147° 52' 30" E
Tanglup, Mount Cone 1160 m 5° 36' 0" S 147° 53' 0" E

Craters

Feature Name Feature Type Elevation Latitude Longitude
Apalong Crater 1454 m 5° 36' 0" S 147° 52' 0" E
Bono Crater 1320 m 5° 34' 0" S 147° 55' 0" E
Pung Crater 1454 m 5° 36' 0" S 147° 51' 0" E
The small circular island at the top-center is Sakar, the NE-most of a chain of volcanic islands off the northern coast of Papua New Guinea. The 8 x 10 km wide island, seen in this Space Shuttle image with north to the upper left, is an incised stratovolcano with a summit crater lake. No historical eruptions are known from Sakar, but a pyroclastic cone on the southern flank of the volcano may be of Holocene age. The 50-km-wide island of Umboi, whose left side is cut by a large caldera breached to the NE, fills the center of the image.

NASA Space Shuttle image STS50-100-D, 1992 (http://eol.jsc.nasa.gov/).
The 50-km-long island of Umboi, the largest of the volcanic islands off the north coast of New Guinea, is seen in this Space Shuttle image with north to the upper right. A large 13 x 17 km caldera cuts the northern half of the island and is widely breached to the NE (top-center). Three youthful post-caldera cones with summit crater lakes (left-center) are visible rising above the smooth-surfaced caldera floor. The large eroded massif at the right-center is an older volcanic complex, as is the dissected northern tip of the island (upper left).

NASA Space Shuttle image STS50-99-748-47, 2000 (http://eol.jsc.nasa.gov/).

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

Fisher N H, 1957. Melanesia. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 5: 1-105.

Johnson R W, Taylor G A M, Davies R A, 1972. Geology and petrology of Quaternary volcanic islands off the north coast of New Guinea. Aust Bur Min Resour Geol Geophys Rec, 1972/21: 1-127.

Lowenstein P L, 1982. Problems of volcanic hazards in Papua New Guinea. Geol Surv Papua New Guinea Rpt, 82/7: 1-62.

Volcano Types

Complex
Caldera
Stratovolcano(es)

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Major
Basalt / Picro-Basalt
Andesite / Basaltic Andesite
Minor
Dacite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
249
1,127
5,585
83,275

Affiliated Databases

Large Eruptions of Umboi Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.