Kadovar

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 3.63°S
  • 144.631°E

  • 365 m
    1197 ft

  • 251002
  • Latitude
  • Longitude

  • Summit
    Elevation

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Most Recent Bulletin Report: March 1981 (SEAN 06:03)


Discolored water

"An area of orange discolouration of the sea at the NE shore was observed during aerial inspections on 6 and 19 March. Previously (1976-77) sea discolouration was present at the S shore and was related to the development of a new thermal area on the S flank of the island. This thermal area was now observed to have been reduced in size by regrowth of vegetation."

Information Contacts: Acting Senior Volcanologist, RVO.

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

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.

11/1976 (NSEB 01:14) Expansion of fumarolic area during September-November

04/1977 (NSEB 02:04) Thermal activity stabilizes

07/1977 (NSEB 02:07) No significant changes in the thermal area

11/1977 (NSEB 02:11) Few changes in the main thermal area; no volcano-seismic activity

05/1978 (SEAN 03:05) Thermal activity declines slightly

09/1978 (SEAN 03:09) Slow decline in thermal activity continues

03/1981 (SEAN 06:03) Discolored water




Bulletin Reports

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


11/1976 (NSEB 01:14) Expansion of fumarolic area during September-November

Kadovar is a 365-m-high, 1.4 km-diameter volcanic island. A 1700 report of smoke seen briefly there was believed at the time to be a volcanic eruption. Since then no eruptions are known, and no traces of thermal activity remained in early 1976, although there was supposedly some such activity several generations ago. The island has the form of a steep-sided cone 250 m high, with a 600-m-wide crater breached to the SSE. The breach probably extended at least to sea level, but the crater and breach are now occupied by a high-standing, conical lava dome. The island is completely vegetated, and supported a village of more than 300 people built around the crater rim. Most of the village gardens are on the side of the dome.

In early August 1976, the first reports were received of activity there, the precise nature of which has not been clearly established. A summary of events to mid-November, and of investigations so far carried out, follows.

May-June 1976. The precise nature of the early events is not clear. Some sort of disturbance seems to have taken place in the sea just off (50 m?) the S coast, which may have been a small hydrothermal eruption or, more likely, a vigorous ebullition of gas bubbles. Weak earth tremors were felt, apparently during the preceding few days, and an explosive sound was heard. Scum was noticed on the water, persisting for a few days, and reddish coloration appeared on the rocks in the tidal zone at one point on the S coast.

August 1976. An investigation [on 3 August] was made by Rabaul Volcano Observatory (RVO) volcanologists D. Wallace and R. Almond. The only effect of the earlier activity was a 100 m-long reddish zone of iron hydroxide discoloration at sea level, and associated sea discoloration. No thermal activity or other unusual phenomena were observed, and no definite volcano-seismic activity was recorded during 5 hours operation of a portable seismograph.

September 1976. Hot ground was first noticed midway up the side of the lava dome about 16 September. An investigation [on 26 September] was made by volcanologist R. Cooke. The coastal discoloration was more extensive than in August, and ground temperatures up to 49°C were present in this zone. The reported hot ground on the mid-slope of the dome was about 30 m x 15 m in area, and was producing vigorous emissions of SO2 and HCl gases (indicated by Dräger tubes) from one main vent and numerous minor vents, at temperatures up to 99.7°C. The white gas column was visible above the treetops from the boat, but only minor vegetation damage had occurred. A newly formed small, weak patch of hot ground was found 100-200 m upslope of the main fumarole area. No volcano-seismic activity was recorded during 5.5 hours with a portable seismograph.

October 1976. Government officers R. Allen and D. Mahar from Wewak inspected the fumarole area [on 14 October], which had intensified in activity and was about 150 x 50 m in area. The expansion had proceeded principally upslope. [On 23 October] D. Mahar again inspected the fumarole area, which had further enlarged. All vegetation in the area had been killed.

November 1976. An investigation [during 10-12 November] was made by volcanologist V. Dent, physicist D. Norris (University of Papua New Guinea, Port Moresby), and D. Mahar. The main fumarole area had enlarged again and was estimated at about 150 x 70 m, and the area of dead vegetation was more prominent. A second main fumarole vent had developed 20 m downslope of the original main vent of September, but the principal expansion since then had been upslope, and to the E. The maximum temperature measured was again about 99°C. Collections of fumarole gas were made in evacuated glass tubes containing silica gel, and gas condensates were also collected. The maximum ground temperature in the S coast discolored zone was 49.5°C, similar to September. About 50 hours recording by a portable seismograph produced 5-10 very small and close A-type events. A seismic event counter was installed on the island. D. Norris carried out a total magnetic field survey of the island using a proton magnotometer.

It is intended to continue regular inspection visits to the volcano, but a full-time observation post is not planned at this time. Such a post will be established, probably on Blupblup Island, 13 km north of Kadovar, when an eruption is believed to be imminent, or once an eruption has commenced. All residents of Kadovar have been evacuated to Blupblup Island.

Information Contacts: R. Cooke, RVO.

04/1977 (NSEB 02:04) Thermal activity stabilizes

"Since the previous report, five more ground inspections have been made, and a sixth is planned for the last week in April. Complete investigations, including temperature measurement, collection of gases and gas condensates, measurement of magnetic field, and seismic recording, were made during visits on 15-16 December (Cooke, Norris), and 16-18 February (Dent, Norris), and are planned for the forthcoming visit (Cooke, Norris). Partial investigations were made on 3 April (Wallace), when temperatures and gases were investigated, and on 26 January (Mahar) and 14 February (volcanological assistant J. Kuduon), when temperatures were measured. Vertical aerial photographs were taken by a survey firm on 15 November, and aerial obliques were taken during the December inspection. Another aerial inspection was carried out on 7 January, the day after a shallow M 6.5 earthquake about 30 km WSW of Kadovar on 6 January, 0611 GMT (preliminary location by USGS). This earthquake had no apparent affect on the volcano at the time.

"During the period covered by this report, the level of activity seemed to have stabilized. Maximum temperatures have been steady at 99-100°C, marked expansion of the main thermal area has ceased (although weak isolated gas vents are still occasionally found in new areas), and the quantity of gas emitted may even have declined slightly. The thermal area was not as unpleasant to the investigators as it was last November-December, although as some gas samples have not yet been analyzed quantitative information on the changing gas content is not available.

"No significant magnetic field changes have been detected. A few volcano-seismic events were recorded in both November and December, but such events appeared to be absent in February. Felt earthquakes were noted by inhabitants of nearby islands on several occasions, but there is no strong reason to associate these with Kadovar volcano. Unusually high seismic event counts on Kadovar are suspect because of a malfunctioning event counter.

"Although the initiation and early rapid development of this thermal activity led to the belief in a forthcoming Kadovar eruption, the stabilization (or even slight decline) in activity suggests the possibility that the event may be confined to thermal activity. Such purely thermal events have been reported elsewhere. However, the event will continue to be treated as a possible precursor to an eruption, and the former inhabitants will be advised to maintain the evacuation for the present. Only a small number of men are presently living on Kadovar in order to maintain the original gardens, to supply the evacuees on Blupblup Island. It is interesting to speculate that the 6 January earthquake may have been connected with the levelling-off of activity."

Information Contacts: R. Cooke, RVO.

07/1977 (NSEB 02:07) No significant changes in the thermal area

"Three detailed investigations have been made since the March report: 25-28 April (Cooke, Norris) 72 hours of seismic recording, gas condensates collected, temperatures measured, and magnetic field re-surveyed; 7-8 June (Dent) 30 hours seismic recording, temperatures measured, and gas and gas condensates collected; and 7-8 July (Wallace, Norris, Emeleus) 30 hours seismic recording, temperatures measured, gas and gas condensates collected, and magnetic field re-surveyed.

"The main thermal area has been little changed during this period. The original fumarole of last September shows the same degree of activity as it did then. Volcano-seismic activity was virtually nil. Maximum temperatures were still 99-100°C but there may have been slight changes in the magnetic field pattern. The only features presently indicating continued development are weak thermal areas that are still being established in new areas on other parts of the island. Some of the population have returned, contrary to a previous report, but they have established a new settlement in a comparatively safe area, having abandoned their old village site."

Information Contacts: D. Wallace, RVO.

11/1977 (NSEB 02:11) Few changes in the main thermal area; no volcano-seismic activity

"Volcanologists have made three detailed investigations at Kadovar since the report in July. On each occasion, temperatures were measured, gases and gas condensates were collected, and seismic recording was carried out; a magnetic resurvey was made during the most recent inspection. Dates and personnel were: 18-19 August, V.F. Dent; 30 September, C.O. McKee; 13-14 November, C.O. McKee and D. Norris. On 14 September, photographs were taken during an aerial inspection.

"The main thermal area was much the same size as before, apart from some expansion at the SW corner, and spanned about 250 m upslope, and about 130 m maximum around the slope. It is now much more sharply defined and clear because of progressive fall of dead vegetation. Overall vapor emission seemed much less than in earlier periods, and was more concentrated in a few main areas, with fewer of the weak but widespread vents evident in early 1977. The original main fumarole may be a little reduced in intensity, although its temperature has not declined, remaining near 100°C. No measured temperatures exceeded 100°C, although the upper part of the main zone has become hotter, approaching 100°C. Vapor emission was still most profuse in the upper part.

"No volcano-seismic activity has been recorded during the report period, and although significant relative changes in total magnetic field have taken place, no simple pattern is apparent."

Information Contacts: R. Cooke, RVO.

05/1978 (SEAN 03:05) Thermal activity declines slightly

Thermal activity was continuing in late March. An aerial inspection 21 March and a ground inspection the next day revealed that although principal fumaroles remained at the same level of activity as before, a slight decrease of activity in the main (S flank) thermal zone is indicated by minor revegetation. The odor of acid gases was no longer present at several groups of fumaroles and temperatures have dropped slightly (from 100 to 97-97.5°C). However, another area of thermal activity (high on the E side of the lava dome) had produced a significant vegetation kill in the past few months.

Information Contacts: R. Cooke, RVO.

09/1978 (SEAN 03:09) Slow decline in thermal activity continues

Kadovar's thermal activity was continuing as of 20 September, but had shown a further slight decline since March.

Information Contacts: R. Cooke, RVO.

03/1981 (SEAN 06:03) Discolored water

"An area of orange discolouration of the sea at the NE shore was observed during aerial inspections on 6 and 19 March. Previously (1976-77) sea discolouration was present at the S shore and was related to the development of a new thermal area on the S flank of the island. This thermal area was now observed to have been reduced in size by regrowth of vegetation."

Information Contacts: Acting Senior Volcanologist, RVO.

The 2-km-wide island of Kadovar is the emergent summit of a Bismarck Sea stratovolcano of Holocene age. Kadovar is part of the Schouten Islands, and lies off the coast of New Guinea, about 25 km north of the mouth of the Sepik River. The village of Gewai is perched on the crater rim. A 365-m-high lava dome forming the high point of the andesitic volcano fills an arcuate landslide scarp that is open to the south, and submarine debris-avalanche deposits occur in that direction. Thick lava flows with columnar jointing forms low cliffs along the coast. The youthful island lacks fringing or offshore reefs. No certain historical eruptions are known; the latest activity was a period of heightened thermal phenomena in 1976.

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
[ 1700 Apr ] [ Unknown ] Uncertain    
[ 1616 ] [ Unknown ] Discredited    

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

Blosseville Island | Keruar
The small circular island at the upper left just above the prominent sediment plume from the Sepik River (lower left) on the mainland of Papua New Guinea is Kadovar volcano. The 2-km-wide island of Kadovar is the emergent summit of a youthful stratovolcano of Holocene age that lacks fringing or offshore reefs. No certain historical eruptions are known; the latest activity was a period of heightened thermal phenomena in 1976. Kadovar is part of the Schouten Islands, along with Blup Blup (upper left) and Bam (upper right) islands.

NASA Space Shuttle image STS106-719-49, 2000 (http://eol.jsc.nasa.gov/).
The small island with the irregular shoreline at the upper left is Blup Blup. This 3.5-km-wide forested island contains lava flows with well-defined flow fronts, and a weak thermal area is located on the west coast. No historical eruptions have occurred, but the volcano may have been active during the Holocene. Blup Blup is part of the Schouten Islands, along with Kadovar volcano (the small circular island to the south, above the prominent sediment plume at the lower left) and Bam volcano (right).

NASA Space Shuttle image STS106-719-49, 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.

Cooke R J S, Johnson R W, 1978. Volcanoes and volcanology in Papua New Guinea. Geol Surv Papua New Guinea Rpt, 78/2: 1-46.

Johnson R W, 1987. Large-scale volcanic cone collapse: the 1888 slope failure of Ritter volcano, and other examples from Papua New Guinea. Bull Volc, 49: 669-679.

Johnson R W, 1990. . (pers. comm.).

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.

Silver E, Day S, Ward S, Hoffmann G, Llanes P, Driscoll N, Appelgate B, Saunders S, 2009. Volcano collapse and tsunami generation in the Bismarck Volcanic Arc, Papua New Guinea. J Volc Geotherm Res, 186: 210-222.

Taylor G A, 1955. Report on Bam Island volcano and an inspection of Kadovar and Blup Blup. Aust Bur Min Resour Geol Geophys Rec, 1955/73: 1-9.

Wallace D A, Cooke R J S, Dent V F, Norris D J, Johnson R W, 1981. Kadovar volcano and investigations of an outbreak of thermal activity in 1976. Geol Surv Papua New Guinea Mem, 10: 1-12.

Volcano Types

Stratovolcano
Lava dome

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Major
Andesite / Basaltic Andesite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
0
0
1,341
114,708

Affiliated Databases

Large Eruptions of Kadovar 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.