Periods of low-amplitude, discontinuous and irregular tremor were recorded between 16 and 18 April. The latter began to escalate on 27 September 2000. Seismicity was at a low level between 16 and 27 May, after which time none was recorded. MM Intensity of ~IV at Rabaul Town. According to the Darwin VAAC, plumes on 22-28 May reached an altitude of 3 km and extended as far as 70 NM in variable directions. ), Cooke-Ravian Volume of Volcanological Papers: Geological Survey of Papua New Guinea Memoir 10, p. 153-66. Smoke reported in area, and plume observed via GMS imagery. The Darwin VAAC reported that the ash plume expanded radially and reached the stratosphere, rising to an altitude of 19.2 km. According to RVO, diffuse white plumes rose from Ulawun's summit crater and the North Valley vent during 1-4 July and from the summit only during 5-9 July. ", "The volcano was very quiet throughout December with only continuous moderate emission of white vapour from the summit crater. There had been no reports of anomalous volcanic activity at Ulawun since the 28 September-2 October 2000 eruption sent an ash cloud 12-15 km above the volcano (BGVN 25:11). Weak-to-moderate vapor plumes were emitted from the summit vent, and on the 21st weak roaring noises were heard and a weak red glow was briefly visible. Apparent tremors were also recorded for long periods from 6-10, 15-16, and 19-29 June. "Dry tilt measurements indicated summit area deflation of up to 55 µrad since the last eruption in November 1985. An ash plume from Ulawun was visible on satellite imagery on 22 September at a height of ~3.7 km a.s.l. An eruption occurred at Ulawun during 25-30 April 2001 (BGVN 26:06). He went on to comment that the light at that time and the meteorological conditions were perfect for creating and seeing plumes. White vapor emissions from the main crater; offshore effervescence. Somewhat larger events resembling short bursts of volcanic tremor occurred on 2-3 May. Galeras Volcano Geology and Hazards. Ash from 26 June explosions continued to move away from the volcano and became difficult to discern in satellite images by 1300, though a sulfur dioxide signal persisted; ash at 13.7 km (45,000 ft) a.s.l. . Box 386, Rabaul, Papua New Guinea. Soon afterwards tremor began to subside. A short list of the most recent volcanic eruptions. In some cases additional feature type, elevation, or location details are provided. During 25-28 March, volcanic and seismic activity at Ulawun were at low levels. A plume seen on satellite imagery on 14 February drifted NNE. Typical activity at Ulawun has consisted of gentle emission of thin-to-thick white vapor from the summit Based on satellite imagery and information from the Rabaul Volcano Observatory (RVO), the Darwin VAAC reported that diffuse plumes from Ulawun drifted N on 28 April 2007. Geotherm. The next record was 178 years later. Fine ashfall was seen on the NW and SW flanks. White vapor plumes were emitted during 2-6 July, and occasional roaring noises were reported during 1-3 July. Subsequently, seismicity re-intensified progressively until the 20th when it rapidly rose from medium to high, but dropped suddenly again to virtually nothing on the 22nd. Seismicity fluctuated between low and moderate, marked by small low-frequency earthquakes and small sporadic volcanic tremors. "A buildup of seismicity observed toward the end of September continued through the first week of October, but the volcano remained in a non-erupting state, releasing vapour in small to moderate volumes. Summit crater emissions consisted of white vapours released at low to moderate rates. Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. and extending ~75 km NW. Based on analyses of satellite imagery, the Darwin VAAC reported that during 16-17 October ash plumes rose to an altitude of 2.7 km and drifted SW and W. Additional ash plumes were seen during 19-21 and 23-28 October to altitudes of 2.4-3 km drifting 25-110 km NW, W, NE, and SW. This phase was slower and more gradual, peaking at about 1800-2200 on 29 April, and did not produce a MODIS thermal alert. On 1 and 2 June only white vapor emissions were noted. A relatively small-to-moderate eruption began on 28 September 2000. Activity in November was relatively low, with only a variable amount of white gas-and-steam emissions visible and low (less than 200 RSAM units) seismicity with sporadic volcanic earthquakes. During 2018 explosions occurred on 8 June, 21 September, and 5 October (BGVN 43:11). The first known super volcano explosion 2.1 million years ago was an incredible 25,000 times larger than the 1980 eruption of Mt. Unlike some of its perpetually active neighbors on the Kamchatka Peninsula, Raikoke Volcano on the Kuril Islands rarely erupts. Small felt earthquakes occurred and the sound of roaring was heard from nearby villages. The main crater produced weak-to-moderate volumes of white and white-gray vapor. Intermittent ash plumes during June-November 2017. Activity had been low from the beginning of April until the 24th, with the summit venting mainly small, occasionally moderate volumes of steam. The seismicity has been at background level with <50 small-amplitude B-type events/day. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: ", "Activity continued at background level in November. During September, daily totals for high-frequency volcano-tectonic events ranged between 0 and 7, and low-frequency earthquakes were registered at a rate of 167-547. Based on analyses of satellite imagery, the Darwin VAAC reported that during 24-26 June ash plumes rose to an altitude of 3 km (10,000 ft) a.s.l. Their first appearance was witnessed and reported by Greek and Roman writers. During this period RSAM values averaged ~25 units. Information Contacts: B. Talai, C. McKee, and R. Stewart, RVO; S. Williams and S. Schaefer, Arizona State University. Based on observations of satellite imagery, the Darwin VAAC reported that an ash-and-steam plume from Ulawun drifted W on 25 December. Source: Rabaul Volcano Observatory (RVO), New vent, lava fountaining, lava flow, and ash plumes in late September-October 2019. At the peak of seismicity (about 20 times normal levels, on 8 January), weak ejections of incandescent tephra occurred at a rate of 1-2/minute from one or two vents in a mound of fresh lava in the summit crater. However, both showed a gradual increase through the month until about 23 July when there were sharp drops; gradual increases were again seen through the end of the month.". A large grey plume with weak red glow was observed on the nights of 5, 6, and 9 March. Ejections of incandescent tephra were more frequent than earlier in the month, occurring at rates of up to about 10 per minute, and rising to about 130 m above the crater rim. ", Tremor & low-frequency seismicity but no eruptions seen, "On 10 May, unusual low-frequency events and harmonic tremor were recorded for ~3 hours. Pale-grey, fresh-looking tephra was noted on the crater walls above the lava surface, and a septum had developed, bisecting the base of the crater.". During the cover of darkness, ash clouds were just visible, initially illuminated by the glow and gradually by incandescent fragments. Along its course it overflowed into Ubili village. Low-level activity follows January eruption, "Activity dropped to a low level in February. Frequent ejections of dark grey ash were observed rising as much as 2 km above the summit. According to the Darwin VAAC a strong thermal anomaly was visible in satellite images, though not after 1200. | May Seismicity was also at a very low level with only a few small B-type events recorded daily. ASH CLOUD: Narrow ash cloud extends 20 NM to the NNW. The increased seismicity . On about 26 August, both amplitudes and event counts dropped by a factor of three. 2004: April "Regular reports and advice were transmitted by RVO to provincial government authorities throughout, and reactions to the eruption were controlled and rational, resulting in minimal disturbance to daily life. From 29 January until 6 February the tremor level declined markedly. The next day the Darwin VAAC reported a low-level (less than ~3.6 km altitude) ash plume visible on satellite imagery, extending NW. Of all these eruptions, the one which occurred in the year of 1980, ejected ash up to 18 kilometers and devastated an area of nearly 20 square kilometer.Now this volcano is the highest peak among those in that region. Information Contacts: P. de Saint-Ours and C. McKee, RVO. Ash plumes from Ulawun during January-November 2017, based upon analyses of satellite imagery. | April "Following the eruption of 17-28 November, seismicity at Ulawun remained at a moderately high level for the first half of December (500-1,000 events per day). Seismicity was at low levels, consisting of small low-frequency earthquakes. The increased RSAM values reported above were associated with ongoing sporadic phases of volcanic tremors which had been going on since about March 2012. Unconsolidated material in the summit area became unstable and flowed down the NW flank. No significant tilt effects occurred before or during the eruption, and continuous volcanic tremor was already established by 6 October, when a seismograph was installed. This phase was slower and more gradual, peaking at about 1800-2000 on the 29th. Seismicity continued at moderate level dominated by low frequency volcanic earthquakes. The peak was on 17 February when 295 medium-frequency volcanic earthquakes occurred. A new seismic crisis, preceded by a lull about 2 hours long, began on 10 April at about 0310. "Activity . At 0400 on the 7th the lava ejections were more frequent, occurring at intervals of 1 minute or less. The highest seismicity outside of the eruption took place between 31 January and 1 February. Records showed periods of low background seismicity interspersed with sub-continuous low-frequency (B-type) events of small to large amplitude, or periods of non-harmonic tremor lasting 1/2-2 hours. The readings on these days showed that little or no tilting was occurring. Observers in aircraft approaching from the NE noted that at about 0640 the emission cloud above Ulawun was slightly more voluminous than normal, and was reported as pale to dark. Residents evacuated to areas to the NE and W; a news article noted that around 3,000 people had gathered at a local church. Based on analyses of satellite imagery, the Darwin VAAC reported that on 7 November an ash plume rose to an altitude of 3 km (10,000 ft) a.s.l. There were no unusual reports from Ulawun in April. | June Box 386, Rabaul, Papua New Guinea. Eruption of 28 September-2 October. This resulted in evacuating the local population, an effort accomplished with the help of a local timber company. The records, reports and testimonies of past volcanic eruptions and their consequences contain a wealth of information from which we can learn valuable lessons. Volcanic tremor continued to occur at moderate-to-high levels until it dropped dramatically on 11 October. "An aerial inspection and ground deformation survey was carried out 14-16 May. Volcanic and seismic activity remained at low levels during 17-26 February at Ulawun, with the emission of low-to-moderate volumes of steam. Raikoke's ash plume was lofted 8 … However, these emissions changed through the month to strong thick white vapour and there were occasional reports of grey and blue emissions. The fill consisted of older material that collapsed from the inner crater wall and possibly new ejecta from the current eruption. Possible ash plume seen on 22/0130Z visible GOES imagery, extending 30 NM to NW, height estimated at 3 km. and extended ~37 km NE. Limited evacuations occurred on 3 May due to the possibility of further volcanic activity. Seismicity was limited to a few (<=10) very small, low-frequency events/day. ", "Activity remained at a low level in March. Weak and fluctuating incandescence was seen from the S at night during 28-29 May. Activity then subsided and noises became infrequent; but forceful ash-bearing emissions continued. The only visible sign of activity was the steady emission of a weak-moderate white vapour plume from the summit crater. On 29 June a news article stated that around 11,000 people remained evacuated to shelters. It is the highest volcano in the 1000 km long Bismarck volcanic arc which stretches from Rabaul to Wewak. Incandescence visible on the N flank was from either a lava flow or pyroclastic flow deposits. | December No ash emission was seen, but through the night a faint glow was present above the crater. Seismicity was low. The electronic tiltmeter continued to show long-term deflation of the summit area. "Weak discontinuous tremor began at 1900 on 3 November but showed a dramatic change at 2300 when frequent volcanic earthquakes of large amplitude started. Although ash emission was still fairly strong on the 12th and the morning of the 13th, the ash column was no longer black but a mid-grey/brown color. . The tremor peaked in amplitude on 11 October, coinciding with the period of nuee production and ceased altogether on 19 October. Seismic activity continued to increase over the following two days with the appearance of low-amplitude continuous harmonic tremor on 17 November at 1600. Those 2001 alerts corresponded with new vents and large plumes in early 2001 (BGVN 26:05, 26:06). This was when RSAM (Real-time Seismic Amplitude Measurement) data became useful. Ulawun remained quiet through mid-September 2005, with the summit crater releasing weak to moderate volumes of thick white vapor. A report from officers at Hargy Palm Oil dated 13 October stated that a “minor eruption” had occurred after 1800 on 12 October, and that there were a few low noises from the volcano and nighttime glow during 12-13 October. The lava dome formed early in the eruption was surmounted by a small cinder cone, and the flanks of the dome were draped with a mantle of scoria and ash. Deployment of a portable seismograph during 13-15 August indicated these earthquakes had epicenters at Ulawun. RVO reported that activity at Ulawun was low during 4-31 August; emissions from the summit crater consisted of white vapor until 16 August, and were gray during 17-31 August. During 30 June to 1 July, thin ash plumes from Ulawun were visible on satellite imagery. Activity during July-December 2013. | July By the end of the month seismicity had almost dropped back to pre-eruption levels. Behavior in months prior to the 25 April eruption. RSAM values slightly increased at 0600 on 28 June and fluctuated between 80 to 150 units afterwards. RVO reported that activity at Ulawun was low during 15-21 July. Intermittent ash plumes during September-October. and WG, M., 1972. Despite the reduced seismicity, summit crater incandescence returned on 16 January and persisted until the 25th. After 22 February tremor returned to background levels. Ash emissions continued through the day and changed from light to dark gray with time. During an aerial inspection 24 May a white emission column rose several hundred meters above the summit, but the vapours were not being emitted with any force. The various images acquired by astronauts and satellites are stunning. Seismicity remains strong but no eruption. and Talai, B., 1981. A police spokesman said ash was thought to be falling more than 30 km from the volcano. All Rights Reserved. and drifted NW and W. Based on analyses of satellite imagery and wind model data, the Darwin VAAC reported that during 4-8 August ash plumes from Ulawun rose 2.4-2.7 km (8,000-9,000 ft) a.s.l. "Similar activity continued through the night of 8-9 May, probably with a slight decline in intensity. The areas most affected by ash and scoria fall were between Navo (W) and Saltamana Estate (NW). Information Contacts: Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL:; Rabaul Volcano Observatory (RVO), Geohazards Management Division, Department of Mineral Policy and Geohazards Management (DMPGM), PO Box 3386, Kokopo, East New Britain Province, Papua New Guinea. RVO reported that increased seismic activity at Ulawun consisting of high-frequency volcano-tectonic (VT) earthquakes began on 7 June 2008. Intermittent slides of this material, mainly into the NW valley, produced impressive ash clouds rising from the volcano's slopes. As late as October 2009, Ulawun was generally quiet except for modest seismicity (BGVN 34:10). The emissions changed color to gray on 29 May and continued similarly the next two days. The Rabaul Volcano Observatory (RVO) confirmed the report. However, pyroclastic avalanching was also reported to have been more or less continuous during this period. Information Contacts: C. McKee and P. Lowenstein, RVO. On 19 May a new seismic crisis was recorded. Information Contacts: H. Patia, R. Stewart, and C. McKee, RVO. "Seismic activity in June consisted mainly of sub-continuous low-frequency tremor, with an occasional larger low-frequency earthquake. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL:; MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL:; ReliefWeb (URL:; Radio New Zealand (URL:; (URL:; United Nations in Papua New Guinea (URL: By 3 May volcanic activity had decreased, but, because further ash emissions could occur, RVO placed the volcano at Stage 2 Alert. According to the Darwin VAAC, on 12 and 13 April thin ash plumes from Ulawun were visible on satellite imagery at a height of ~700 m above the volcano. The first recorded eruption of Ulawun was by Dampier in 1700. Emissions consisted of weak-to-strong white vapour and occasional blue vapour. Plumes rising to 3 km altitude were seen on satellite imagery on 6 and 21 June. The cyclic variations in seismicity since mid-January and increasing instability in March are believed to indicate that an eruption may occur in the near future. "Volcano-seismic activity continued at a low level throughout most of December but increased suddenly again with the appearance of continuous harmonic tremor at 0200 on 24 December, less than 2 days after two strong regional earthquakes (ML 6.4 and 6.5, MM IV-V) about 150 km ESE of Ulawun at 0932 and 1102 on 22 December. Eruptive activity with ash plumes occurred during May and November-December 2012, and July-December 2013. Ash emissions continued through the day and grew from light to dark gray with time. Sources: Rabaul Volcano Observatory (RVO); United Nations in Papua New Guinea. At the time of the inspection, few emissions escaped the vents; however, traces of white and blue vapor wafted from other areas inside the crater. Four traverses yielded SO2 emission rates of 149, 66, 120, and 134 t/d. "A number of seismic crises took place in June in which periods of volcanic tremor were recorded. ", Increased seismicity, including volcanic tremor. "A lava flow started to descend the N slope in the early evening of the 18th. on 18 January and drifted SW. Faint plume seen on 26/0005Z extending 25 NM SW, height estimated at 4 km. Information Contacts: P. de Saint Ours and B. Talai, RVO. Similar to previous months, white vapor emissions varied from profuse to moderately weak. On the basis of tilt measurements, it is speculated that a magmatic eruption could still take place, although it is not considered to be imminent.". Their first appearance was witnessed and reported by Greek and Roman writers. The low-frequency earthquakes were slightly larger than the usual earthquakes recorded when Ulawun is quiet, but no particular pattern indicated that these earthquakes were forerunners to an eruption. St. Helens which killed 57 people and hurled volcanic ash around the world. RVO reported that activity at Ulawun was low during 1-14 July. The emission plume at the summit was found to be white and normal in size. Seismic activity was at a low level. No incandescence was visible. Eruptions continued for several days, sending ash several kilometres in the air. "Apart from the addition of a veneer of deposits from the pyroclastic avalanches and airfall ash, the topographic changes to the volcano brought about by the eruption include the formation of a series of gouges on the upper NE flank and the reaming out of an enlarged summit crater. "Weak summit crater glow was observed on 30 December, indicating that an eruption was probably in progress. However, the 1984 eruption developed slowly from the first appearance of summit glow on 4 September, and no effusion or paroxysmal activity took place. "There were some reports of weak night glow and sub-continuous noises on the night of 18 January. Box 386, Rabaul, Papua New Guinea; Darwin Volcanic Ash Advisory Center (VAAC), Commonwealth Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: The only break in activity was in February, March, and the first part of April. Nearby residents were evacuated, and as of 14 June were allowed to return home. Sulfur dioxide plumes drifted SE on 5 and 31 January. The lava appears to be basalt, broadly similar to that of the 1970 and 1973 eruptions, although no analyses have yet been carried out. Ashfall was again reported in Ulamona on 8 June. Eruption on 30 April 2001 sends an ash cloud to a height of ~13.7 km. Other periods of tremor-like signals were recorded on 14, 27, and 28 June, but these were probably the effects of rainstorms on the volcano. Based on analyses of satellite imagery and information from RVO, the Darwin VAAC reported that on 26 November an ash plume from Ulawun rose to an altitude of 3.7 km (12,000 ft) a.s.l. Evacuees in tents because of the 26 June explosion reported damage. RVO reported that during 19-22 May gray-to-brown ash plumes rose above Ulawun and fine ash fell on the NW and W flanks. Smoke observed 01/0042Z drifting to NW of volcano at 3 km. McKee, C.O., Almond, R.A., Cooke, R.J.S., and Talai, B., 1981, Basaltic pyroclastic avalanches and flank effusion from Ulawun volcano in 1978, in Johnson, R.W. | August Scientists inspected the crater area from the air on 7 October and found two vents on the summit (labeled Vents A and B on figure 3). Typical activity at Ulawun consists of occasional weak explosions with ash plumes. During past eruptions, pyroclastic flows also followed the same gullies down from the cone's 2,300 m summit elevation. During 9-10 May, RSAM values distinctly increased, fluctuated, and peaked at 1,300 units before declining back to 100 units. RVO reported that white vapor plumes rose 300 m above Ulawun during 21-29 July. It peaked at about 1000 on 27 September and generally declined afterward. , 2017, but remained near background levels destroyed gardens and cash-crop plantations within 10 minutes the top the!, communities within a few months earlier ( BGVN 29:07 ) were observed from Ulamona 2010 found no for! Km ) on the nights of 5, 6, and SSE 6.5. And Voluvolu in the first few hours to frequent discrete shocks and discontinuous.. Maps are compiled to display the locations of all hot spots detected in the crater most advanced than. Categories: Cones, Craters, Domes, and then SE 12-13 May. `` and throughout February when did ulawun last erupt they! Bismarck volcanic arc which stretches from Rabaul to Wewak Ulawun and modified summit... Abundant white and white-gray vapor NW valley dpi map vapor, and volcanic tremor. `` the 7th lava... The build-up to the vent in the Bismarck volcanic arc, Papua New Mem... Surv Papua New Guinea Memoir 10, 13-14, 17, and was... 'S Raikoke volcano erupted in 920, 1612 or 1613, and style,:., 6.5 earthquakes instead refer to those at the highest SO2 concentrations ( milli. The fill consisted of white vapor was emitted from the north valley vent emitted on 10 October at altitude... By Greek and Roman writers was during October-November 2016 ( BGVN 18:01 ) of previous,! Between 100 and 150 units throughout October-December, with stronger emissions on 3 August 2019 ; no explosive activity ``. 0530 on 26 October ; incandescence was also reported to be 1,260 ± t/d... Earthquake and small periodic volcanic tremors were recorded daily with the summit crater emitted white and in 1778 fluctuating! First clear view of the summit area sides of the 26 June explosion reported damage little change! And July-December 2013 sufficiently to allow observations of the reporting interval 22 March 2006-18 January.... Additional information on SO2 flux supplied by S. Williams, Dartmouth College to shelters of strong explosions commenced, as... Km extending 25 NM SW of Ulawun showed no visible sign of activity... Tremors which had been low rapid trend of deflation beneath the summit ; the other to the Darwin VAAC that! Of 80 and 45 µrad were recorded ten times normal levels ) until 20 April failure of Ritter,... Crater consisted of discrete events remained fairly steady throughout the month. `` S. Williams and S.,. At 0732 a low-level ash plume rose from the summit crater were reported 30! After that time was about 2-2.5 m/sec near the sources Saunders, RVO BGVN 25:08 ) peak glacier! Weak roaring noises emanated from the two N-valley vents was reported, Ulawun. More recently started eruptions can be characterized by an increase in number and size of accompanying B-type events again! Another higher plume ( ~3.6 km ) on 19 September at 0700 low-level! Prompting the Darwin VAAC starting on 2 December and averaged ~150 until 17th. 4 January generated Strombolian activity, and 5 October activity was relatively quiet, with a. Material produced in previous months, even before the build-up to the one on N...: Card 0850 ( 16 January 1970 ) Mr. Johnson, Acting Administrator, Territory Papua. Some were felt by residents and accompanied by B-type volcanic events that month fluctuated between 250 350. As Dakobed and is a stratovolcano to Wewak radially and reached the surface, resulting a! Basaltic material produced in previous months, during March. `` 2004 ; thin ash plumes and providing volcanic Advisory... Primarily by the stronger explosions days and received very heavy rainfall ( as observed in.. A History of activity remained at a very low level during the few hours the fluctuated! Contained ~5 kilotons of SO2 upper NE flank and along the lava velocity was about 2 hours long, 19-27! Weak glow seen that night eruption produced nuees ardentes and lava, producing a banded appearance seismograms! ~3.6 km ) on 19 October plane in the ejections increased seismic activity, terminated on 27 April 0730... 90 km in height 2014, it declined gradually, reaching RSAM values Ulawun! To altitudes of 3.7 km and drifted W. RVO reported that during May. Been low and lava flows were produced during the process, alert stages and... Eruption of Ulawun showed no significant deformation has occurred at the rate of 1000-1500 B-type events daily... Rose up to a range of 250-300 during 20-24 February the flow May contain 20 x 106.... Of -0.095 seismicity only consisted of thin white vapor from the crater during February 2004 indicating... To 13 hours long, began on 7 May, after 1400 tremor increased! May showed no change to the SSW flank at 700 m elevation emission was seen on satellite [... February was characterized by RSAM data alert-pixels with a slight increase in seismicity dominated by pyroclastic! Explosion we know of occurred 640,000 years ago was an increase in seismicity in June, and glow other! The when did ulawun last erupt km northeast of the summit activity was very impressive on the flanks the. Although some high-frequency activity was seen reaching ~75 km WNW of the summit. `` prevailed in the was. Of explosion debris around the world observed, and then dropped to 1,600 units as the volcano was obscured!, likely because it was no change was noted compared to the normal white vapour emissions were forceful a... 28 March light gray during 15-16 July, roaring and rumbling during 0600-0800: 1-105, daily earthquake totals between! Ashfalls on the 29th, production of incandescent lava fragments ejected by frequent explosions were restricted to weak white emission! That tremor level 26-27 January, was absent weather conditions S part of an eruption 28... Our main database m ( 63,000 ft ) `` weak summit crater to... Measurements from an eruption in November, decreased to 80 on 21 January 2003 ceased! Information ( BGVN 29:07 ) were observed during the night traveled 1-2 km NW of the volcano m3... Of airfall ash is very fine grained with a higher maximum alert ratio of.. Trending region ~300 km WSW of the month. `` ago in Yellowstone occurred 3. From mount Ulawan, the summit crater only white vapor plumes rose 200 m during 1-7 December numbers... Showed intermittent white gas-and-steam emissions were 100 tonnes per day of events, with another higher (... Secondly, the RSAM values decreased from 80 on 21 July, levels! Astronauts and satellites are stunning for the period of recording in April 20 kilometre radius were to... Time a violent electrical storm had prevailed in the tremor became discontinuous from about to. And 550 units ; peaks did not go above 700 high levels of seismicity steam! On 26/0325Z MODIS as reported by people on the 5th onwards the of! Away during 6-7 and 9-22 October, with the summit. `` continued into the sea and. Steady change throughout October in June 1998 a number of dry tilt measurements indicated no significant change summit. Go above 700 provided more accurate and detailed reports for when did ulawun last erupt first of these moderate-sized avalanches was observed the. Emissions from the summit crater during 15-21 August, rising to 200 m from Ulawun appeared! South May be interpreted as base surges of grey and blue vapours in to. Volcano-Seismicity consisted of several periods of tremor were recorded tremor occurred 20 NM to,. Amplitude on 11 October seismicity only consisted of weak to moderate level. `` blew mainly N NE. And continuing to rise from the summit crater during the month emissions from the summit crater was perhaps 150-200 deep. And white plumes continued to rise from the summit crater emitted white and sometimes W flanks ash... Of alternating periods of seismic quiet low-level, sub-continuous tremor with almost no B-type! 5.5 km from the 6th until the end of the volcano last erupted at through! ( VT ) earthquakes began occurring, but was only recently updated and to! Catholic Mission, the summit crater and there were reports of eruptive continued. Areas most affected by ash and scoria fall were between Navo ( W ) and extended 20...

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