New Activity/Unrest: Kilauea, Hawaiian Islands (USA) | Klyuchevskoy, Central Kamchatka (Russia) | Merapi, Central Java (Indonesia) | Piton de la Fournaise, Reunion Island (France)
Ongoing Activity: Agung, Bali (Indonesia) | Aira, Kyushu (Japan) | Ambae, Vanuatu | Dukono, Halmahera (Indonesia) | Karymsky, Eastern Kamchatka (Russia) | Langila, New Britain (Papua New Guinea) | Mayon, Luzon (Philippines) | Reventador, Ecuador | Sabancaya, Peru | Sheveluch, Central Kamchatka (Russia) | Turrialba, Costa Rica
The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.
Kilauea | Hawaiian Islands (USA) | 19.421°N, 155.287°W | Summit elev. 1222 m
HVO reported that the eruption at Kilauea's Lower East Rift Zone (LERZ) and at Overlook Crater within Halema`uma`u Crater continued during 23-29 May. Lava fountaining and spatter was concentrated in the middle portion of the fissure system, feeding lava flows that spread through Leilani Estates and Lanipuna Gardens subdivisions, and also traveled to the ocean.
Earthquakes beneath the summit and ash emissions from Overlook Crater continued as the summit area subsided and adjusted to the withdrawal of magma. Ash emissions were small and frequent, punctuated by larger plumes. The Overlook crater vent continued to widen to the W, and by 25 May the vent area was about 36 hectares. At 1244 on 25 May a M 4 earthquake was located in the summit region. That same day a new pit opened on the N part of Halema`uma`u Crater floor. Three explosions (at 0042, 0144, and 0500) on 26 May generated ash plumes that rose 3-3.3 km (10,000-10,800 ft) a.s.l. A small explosion at 0156 on 29 May sent an ash plume vertically to 4.6 km (15,000 ft) a.s.l. and drifted slightly NW. The explosion was felt by residents in Volcano, and ejected incandescent blocks within Halema`uma`u Crater. On 28 May a M 4.1 earthquake occurred at 1739 along the Koa'e fault zone, S of the caldera.
Lava fountains from Fissure 22 continued to form a channelized lava flow that entered the ocean NE of MacKenzie State Park, causing explosions and generating a plume of hazardous laze (lava haze, a mixture of condensed acidic steam, hydrochloric acid gas, and tiny shards of volcanic glass). On 23 May relatively tall lava fountains at fissures 6 and 13 fed another channelized flow that created a second ocean entry. Observers noted that a perched lava pond/channel was 11 m above ground level, and that methane was seen overnight that burned blue in road cracks. On 24 May lava was entering the ocean at three points between Pohoiki Bay and MacKenzie State Park, though by the next day only two were active.
Overnight during 25-26 May vigorous spatter was observed from a cone on Fissure 8, and multiple booming gas emissions occurred at Fissure 17. By the morning of 26 May an estimated 9.6 square kilometers had been covered by new lava. Fissures 7 and 21 fed a perched lava pond and sent flows NE; the lava-flow fronts became 'a'a. A perched pond on the W side of Fissure 7 was breached, sending short flows W. Later that day the flows turned S, and by dusk were cascading into Pawaii crater, adjacent to the W margin of the Fissure 6 flow that fed one of the ocean entries. Lava from Fissure 21 flowed onto Puna Geothermal Venture (PGV) property.
During 26-27 May activity at Fissure 7 increased; lava from fountains 45-60 m tall built a large, 30-m-high spatter rampart. Large cracks were observed overnight on Kupono St., near Fissure 9. Three vents active at Fissure 8 spattered and flamed, and doubled in size in one day. On 27 May lava flows from fissures 7 and 8 advanced NE on PGV property; at about 1900 a flow broke out in this area and advanced rapidly to the N and W, through the E portion of Leilani Estates, prompting several residents to evacuate. Three minor ocean entries were again active. Fissure 24 opened in Leilani Estates.
On 28 May the vents that fed the ocean entries stopped erupting, leading to only residual lava in the channel to occasionally enter the ocean. During 28-29 May fountains, lava flows, and spattering from multiple fissures persisted. Pele's hair from vigorous fountaining (60 m high) at Fissure 8 drifted downwind, with some strands falling in Pahoa. According to a news article, the LERZ eruption had destroyed at least 94 structures, including 53 homes, by 29 May. The flows also cut off road access to PGV, which had been evacuated.
Geologic Summary. Kilauea, which overlaps the E flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halema`uma`u crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 km2, destroying nearly 200 houses and adding new coastline to the island.