Since 4 April, no ash plumes / explosions have been reported from the volcano by Tokyo VAAC. This marks one of the longest intervals of relative quiet, i.e. absence of small to moderate vulcanian explosions, in a long time. ...
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Vulcanian explosion-type eruptions have been relatively infrequent recently (only 0-2 per day), but some of them produced ash plumes rising as high as 12,000 ft (3.7 km) altitude.
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2006-2010 Activity: moderate explosions at 1-5 days intervals
Moderate explosions with typical plume heights of around 2 km occured every 1-5 days during most of 2006-10. In 2009, a slight increase of activity was observed. Plume heights of explosions reached a maximum of 5 km altitude (4 km height).
[hide] On 9 April 2009, a vulcanian explosion produced a pyroclastic flow to 1 km to the east and bombs were thrown to up to 1.3 km distance. Heavy ashfall occurred at Kagoshima City. The ash plume reached 5 km altitude a.s.l.
4 June 2006: first eruption outside the summit crater in 58 years
On 4 June 2006, Sakurajima erupted from a small vent outside the summit crater, near or within the crater which erupted the 1946 (Showa) lava flow on the E slope of Minami-dake summit. The eruption continued intermittently until the next morning.
Activity in 2000-2005
Sakurajima returned to low to medium levels of activity, with 150-200 eruptions per year. Occasional stronger explosions, such as on 7 October 2000, caused eruption columns as tall as 5 km above the crater, abundant ash falls, and damage windshields to cars.
Oct - Dec 1999 eruptions
Vigorous activity began in October 1999, marked by lava fountains and large large amounts of ejected ballistic bombs, blocks and lapilli falling as far as 4 km from the crater.
[hide] The total of 88 explosions during December 1999 was the second highest monthly count since 1955; the highest was 93 explosions in June 1974.
Activity in the 1990s
Compared to the 1980s, activity remained at lower levels at Sakurajima in the 1990, with explosions often occurring only at intervals of several days. Long pauses in explosive activity characterize the year 1995.
[hide] 1996-99 eruptions: low activity Activity remained generally at low to moderate levels. Only 35 explosions occured in 1997. An eruption on 16 May 1997 sent an ash plume 3,500 m above the summit and threw blocks and bombs to up to 2 km NW of the crater. Activity increases in Oct 1999. The number of eruptions in 1999 was 386, including 237 explosions.
Sakurajima volcano had a heightened level of activity during the period 28 July-12 August 1999. Large eruptions occurred on 30 July, 1 August, andon 2 August when ballistic ejecta fell as far away as the mid-flank of the volcano.
1995 activity: more than 200 explosions About 20 explosions occured on average in the first half of the year, producing ash plumes up to 4 km high. Explosive activity 23-25 August produces heavy ash fall, forcing the closure of a road.
The Sakurajima Volcanological Observatory, Kyoto University, estimated the total amount of erupted material at 3-4 million tons, and observed continuous uplift on the N side of the volcano, implying accumulation of magma beneath the volcano.
1994 activity: 277 eruptions (148 explosive) Volcanic activity remained low in the first half of the year, resuming vigorous explosions in June-July and throughout the rest of the year.
1993 activity: few eruptions (total 91) Activity quieted down at Sakurajima. Long periods with no explosions or only calm ash emission occur, the longest being 201 days long until activity resumed on 20 October. This was the longest quiet period since the 307 days from April 1971 until March 1972.
1992 activity: 165 explosions 60 explosions were recorded in January, the highest monthly total since December 1985. A car windshield was cracked by lapilli during an explosion on 2 January. Activity decreased significantly in February and pauses again to moderate levels in October.
1991 activity: 295 explosions Explosive activity remained at high levels since mid-January. An explosion at 23h45 on 29 June ejected blocks and lapilli that damaged house roofs and two car windshields. Tephra from an explosion on 5 August hit the windshield of a Boeing 737 airliner 13 minutes after the eruption as it flew at an altitude of 1.2 km, 10 km N of the volcano. A crack 50 cm long was created on the outer surface of the windshield, but the plane landed its 122 passengers and five crew safely.
Activity decreased in August and started to increase again in December.
1990 activity: 119 eruptions
After a relatively calm period, stronger explosions occur in August. On 28 August at 02h30, a large explosion ejected many blocks to the middle flank of the volcano. Twenty lightning flashes were seen in the volcanic cloud. Two car windshields were broken by lapilli 4 km from the summit and two blocks, roughly 60 cm across, fell 3 km S of the summit.
No explosions were recorded in September. The volcano exploded only once in October, on the 4th, following 37 days of quiescence.
Strong explosions on 30 November occurred after 57 days of quiescence. The ash plume rose more than 4,000 m, and lapilli / blocks fell 3 km S of the crater (at Arimura) and broke 4 house windowpanes and 13 car windshields.
Sakurajima had 4 eruptions in December (4, 25, 26 and 28 Dec.), but these were relatively strong. Plume heights reached 4 km and falling lapilli broke car windshields in up to 5 km distance.
Activity in the 1980s
Explosions continue to occur typically one per day or two. Between 1985 and 1987, the activity produces particularly violent eruptions, peaking in November with 3 powerful explosions that cause much damage to cars and houses by impacting volcanic bombs.
[hide] 1988-89 activity: explosions decrease
Both the number and size of explosions decreased compared to the activity of intense eruptions in 1985-1987.
1987 activity: powerful explosions, peak of activity in November Strong eruptions such as one on 24 September cause loud bangs and air shocks. Lapilli, as large as 10-20 cm long, falling from the explosion broke several car windshields and damaged houses. A large amount of lapilli fell on the road from WNW to NW of the summit.
Three explosions in November were particularly strong. The first, at 15h36 on 14 November, ejected a large amount of ash to 3.2 km height. Lapilli broke car windshields in the S part of the island. An explosion at 20h56 on 17 November was the largest of 1987. An incandescent lava fountain reached 1 km, the highest since frequent explosions began in 1955. Large numbers of incandescent blocks were ejected for about 2 hours, burning cars parked at the foot of the volcano. More than 70 instances of volcanic lightning were observed in the eruption cloud. Eight car windshields and 23 solar water heaters were cracked by lapilli. A traffic accident, where a truck lost traction and crashed into a house, was attributed to volcanic ash that had fallen on the road. At 11h19 on 28 November an explosion broke eight house windowpanes in Tarumizu city, 10 km SE of the summit. A window in a hotel on the S part of the island was cracked by the air shock.
1986 activity: strong explosions continue At 16h02 local time on 23 November an explosion ejected a 2.5-m-diameter block onto a one-story concrete building at the foot of Sakurajima volcano, 3 km S of the crater. Six people in the building were injured as the block, estimated to weigh 5 metric tons, broke through the roof and ground floor of the hotel and landed in the basement. Two other large blocks (1-1.5 m diameter) landed near the hotel and created an impact crater and started a grass fire.
A total of 131 explosions were recorded January-June 1986. Lapilli from an explosion on 10, 12 and 24 June broke windshields of 12 cars and damaged roofs of about 30 houses near the volcano. Ash from the explosion on 12 June fell heavily at Kagoshima City.
A TOA Domestic airlines DC9 with 152 passengers and a crew of six flew into the 24 June cloud at 1,200 m altitude, 23 minutes after it was ejected. Cockpit windshields and front surfaces of wings were badly scratched by ejecta. The airliner, en route from Fukuoka, landed safely at Kagoshima. Similar accidents had occured 8 times before at the volcano before.
6 explosions were recorded during December, bringing the 1986 total to 213.
1985 activity: powerful explosions An strong eruption from the summit crater happened on 24 February, producing an ash plume reaching 4 km height. Lapilli 4-5 cm in diameter fell as far as 5 km SE of the crater, damaging 43 cars at the S foot and in Tarumizu City (5 km SE). Bush fires were started by incandescent tephra. Bombs fell on roads and farms producing large impact craters. A bomb from an explosion on 8 June at 1316 made a 1-m-diameter crater in a road near a residential area. On 13 June, lapilli up to 3 cm in diameter fell on the S foot of Sakurajima, cracking windshields and solar water heaters on rooftops. Ash fell heavily in Kagoshima and closed railway crossings.
In total 474 explosions were recorded in 1985 and cumulative ashfall was 15,908 g/m2, the largest since the summit eruptive activity began in 1955.
1983 activity: Large eruptions in May 1983 The activity was accompanied by thunder and temporary interruption of electric and telephone service. A large amount of ash fell SSE of the volcano; more than 20 car windshields were broken, and the roof of a primary school cracked.
1981 Eruptions: strong explosions in January Four strong explosions occurred on 18 January, producing short lava fountains of 200 m height.
Lapilli from an explosion on 21 November 1981 broke windshields on cars passing 3 km S of the summit.
1980 activity: largest number of explosions/month in five years in May
After a decrease in frequency in Feb 1980, eruptions intensified in May 1980 (69 explosions) and decreased again to 12 explosions in June.
Lapilli from an eruption in November 1980 broke five car windshields. The air shock from a 28 November 1980 explosion broke two windows in a hotel at the base of the volcano.
Sarkurajima's activity was characterized by typically one explosion per day. THe largest eruptions produced plumes up to 4 km high, and on several occasions, landing aircraft at Kagoshima airport were damaged when flying through ash.
The eruptions caused no fatalities, but damaged cars, windows and crops in the immediate area around the volcano.
[hide] 18 Nov 1979 eruption The windshields of two domestic airliners were cracked as they flew into an eruption cloud near Sakura-jima at 08h01 and 08h05 local time on 18 November 1979, about 20 minutes after a recorded explosion. In both cases, damage was restricted to the outermost of three sheets of glass, and the planes landed safely.
A similar accident occured on 24 December 1979: the windshield of a domestic airliner was cracked by tephra at 1.5 km altitude, 9 minutes after an explosion from Sakura-jima. The plane landed safely at Kagoshima airport 7 minutes later.
1978 activity: 231 explosions total Frequent explosions and continuous ash emissions occur in August. Ash fell every day around the volcano, primarily to the NW, causing slight damage to crops, electric wires, and homes over a broad area.
In December, the number of explosions increased. Lapilli ejected on 4 December cracked 2 windshields of All Nippon Airways airplanes. Similar damage to aircraft above Sakura-jima occurred on 8 April 1975 and 25 December 1977.
1977 activity: small to medium explosions alternate with occasional stronger ones, producing plumes up to 2-3 km high. The air pressure shock wave from an explosion on 30 November broke 102 windows in villages 3 km from the summit. Strong activity continues in December and into January 1978.
1976 activity: In May 1976, two larger explosions damages car windows and crops. On 13 December, falling lapilli (4.5 cm diameter) broke car windows 3.5 km E of the summit.
Sep-Oct 1972: strong activity Sakurajima produced a series of strong explosions with ash plumes reaching more than 4 km height. On Oct 2, the largest explosion since November 1957 occured.
1971: Two small lava lakes were active at Sakurajima.
