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On the 12th July the writer was informed by signal originated by the A.D.O. Baluan Island, that explosive activity had recommenced at the St. Andrew Strait vents. The writer departed Rabaul by air from Momote on the 14th July and arrived at Baluan per Administration work boat on the evening of the 15th July. En route to Momote on the evening of the 14th a brief aerial inspection was made of the active area. Two small craters were visible above sea level and some minor explosions originated from the western crater during this inspection. The writer spent one week in the area and departed Baluan on the 21st July. During this period, as no further explosive activity was manifest, two ground inspections were made of the western crater. The day after the writer departed Baluan mild activity (mainly effusive) recommenced at the eastern crater. The name Tuluman (Tuluman being the word for hot in the Manus language) has been proposed for this new volcano. The name embraces the whole of the structure, that is, the two small cones above sea level as well as the submarine portion of the structure. The two small structures above sea level are referred to as east and west Tuluman craters respectively.

On the 4th November, 1954, the first report of eruptive activity at Bam Island was received at the Observatory, Rabaul. Mr. M.A. Reynolds was at that time engaged on an investigation at Tuluman Volcano, Manus Sub-district. As he had most of the field equipment with him the writer signalled a request to him to proceed to Bam to investigate this report. On the afternoon of the 5th it was learned that the Lorengau radio was out of operation and that Reynolds had not received the signal. The writer departed Rabaul at 0700 hours 6th November, 1954, and arrived at Wewak at 1200 hours. The m/v. "Ella" was made available and the writer departed Wewak at 0300 hours together with Cadet Patrol Officer R.G. Noble for Bam Island, arriving there at 1300 hours that day. The writer spent a little over a day on the island and returned to Wewak on the 9th November. The recent investigation revealed that the present activity consists of only mild explosions, ejecting well crystallised lava, which though incandescent when ejected was solid. Seismic activity only accompanied the actual exposions and was not premonitory.

No details are available of the previous volcanic activity of Vitu Island, but some old natives have stories of unusual phenomena referable to vulcanism which accompanied a change in sea level many years ago. The inference of the stories was that the change was sudden and accompanied by increased emissions of steam from Zones A and B (of this report). It was impossible to assess from natives interrogated how long ago this occurred, but palms estimated to be about 40 years old grow near the shore in the area to which the stories refer. This area embraces the Catholic Mission, Balangori No. 2 village and Mt. Utopi, and, according to legend, most of the coastal portion to an height of about 300 feet was previously submerged. A more detailed survey of the island would be necessary to establish the veracity of the stories, but there is certainly evidence that portion of the area was submerged. Old oyster shells occur to heights of about 30 feet above sea level attached to basalt cliffs below the Catholic Mission. Since it was necessary for the "Theresa May", on which the writer was travelling, to visit the Vitu Island Group on the return trip from the Langila Crater investigation, the advantage was taken of examining as many thermal areas as possible. Although geysers and fumaroles occur on Narage Island, the northernmost island of the group, it was possible only to examine briefly those areas on Vitu (Garove) Island in the time available.

The 1954 investigation was primarily concerned with examination of as many of the thermal areas as possible in the short time available, and to record temperatures which could be used as a basis for comparison in future investigations. The writer arrived at Talasea on the "Theresa May" on the 28th August after completing investigations in the Langila Crater area and on Vitu Island. Over the next three days thermal areas near Talasea and west of Pangala village on the north coast of Garua Harbour were visited and temperatures taken.

This report deals with the volcanic activity at Tuluman Volcano in St .Andrew Strait, 25 miles south of Lorengau in the Admiralty group. In the first of the three papers, which constitute the report, a description is given of the activity from June 1953, when the eruption began, to the end of July-1954. Part II describes further submarine activity in October and November 1954, and the condition of the active centres at that time. In Part III a more detailed description of the eruptive activity is given and the eruption and the associated phenomena are reviewed at some length. Volcanic activity in the St. Andrew Strait has originated from at least five, separate centres, from one of which another cone has been formed by a branching-off from the main conduit. As a result, three islands, two of which have been subsequently joined, have been built up above sea level. The name Tuluman Islands is proposed for these islands, and individual cones are numbered according to the chronological order in which they have been formed. The geographical position of the Tuluman Islands and their topography are also discussed.

Assessment of existing volcanic ash hazard models for South East Asia: towards development of an open-source, volcanic ash impact computational model for Indonesia

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