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Observations & impacts of the 2017–2018 Ambae, Vanuatu eruption - Volcano Watch

2:04 AM · Sep 24, 2021

The Pacific is home to dozens of active volcanic systems including the massive Hawaiian shield volcanoes Kīlauea and Mauna Loa. Most basaltic shield volcanoes in the Pacific are related to the hotspots that created the Hawaiian Islands and many of the Polynesian and Micronesian island chains. These massive hotspot shield volcanoes are built largely by eruptions of lava that are periodically interrupted by cycles of explosive activity. There are other large shield volcanoes found along subduction zones rimming the Pacific Ocean, but they can behave very differently from Kīlauea and Mauna Loa. The island of Ambae, in Vanuatu, is a large basaltic shield volcano that lies along the subduction zone between Fiji and Papua New Guinea in the South Pacific. Since 1995, Ambae has experienced explosive episodes once or more per decade. In physical form, Ambae looks like a smaller version of Mauna Loa. The island is 9 miles (14 km) wide and 24 miles (39 km) across (see figure) with gentle slopes and dense vegetation. Like Mauna Loa, the summit has more than one large crater. The craters at Ambae are filled with colorful lake water which testifies to a deep system of heated, sulfur-rich groundwater beneath the summit. At Ambae, these large crater lakes and associated groundwater contribute to a specific style of activity called phreatic or phreatomagmatic eruptions. Ambae had two strong episodes of moderate to large explosive eruptions in 2017–2018 after mostly minor activity during the previous decade. The first episode occurred in October 2017 and covered the island with ash, gas, and acid rain causing crop damage, water fouling, and respiratory concerns. These impacts, compounded by a lack of new rainfall to replace affected drinking water, forced the evacuation of about 11,000 residents beginning in late 2017. Eruptive activity waned shortly after, which prompted the local population to begin to return to the island around the start of the new year. Eruptions and their impacts in Vanuatu are monitored by the Vanuatu Meteorology and Geohazards Department (VMGD) using transmitted seismograph (ground shaking) data and periodic island site visits by volcano scientists. After the first episode, low-level volcanic activity continued with minor gas and ash discharge from the volcano. Remobilized ash also turned into mudflow lahars throughout the rainy season, from October to April. In July and August 2018, VMGD and a New Zealand-based research team arrived at Ambae to collect ash and water samples, acquire seismograph and acoustic (sound) data, and document the impacts of the eruptions. By coincidence, the field teams and local residents were met by new and increasing explosive eruptions. The largest of these eruptions produced ash plumes over 9,100 meters (30,000 ft) above sea level which affected South Pacific airplane traffic. The newly deployed seismic-acoustic array captured most of the second phase of eruption and these data were subsequently analyzed by researchers from New Zealand, Vanuatu, and the United States. The data showed in detail the timing and size of explosions on the volcano. An example time record for one of the eruptions is shown in the figure which documents a previously unrecognized event. The data show not only the ground shaking from the eruption but also the sounds of the volcano. At present, monitoring in Vanuatu is ably conducted by real-time observation of transmitted seismic data to the remote monitoring center in the capital of Port Vila. Acoustic observation of Vanuatu volcanoes is in its infancy, but the temporary deployment illustrates the value of such data for monitoring purposes. The new eruption phase ultimately forced the second full evacuation of Ambae in August 2018. Interestingly, while the 2018 eruption on the Island of Hawai‘i received global attention, the Ambae eruption had a larger global impact due to the huge amount of gas released. Fortunately, the eruption ended later that year and local Ambae residents were able to return safely to their homes. In late September 2019, scientists returned to Ambae to remove the temporary seismic and acoustic stations. Local farmers, who had returned earlier in the year reported abundant crops, possibly a result of the newly rejuvenated ash-rich soils. IMAGE AND CAPTION FROM USGS: Ambae Island is in the northern Vanuatu archipelago (Figure A, courtesy of NASA) and hosts a nested caldera at its summit. A temporary seismic-acoustic array was deployed beginning July 2018 (yellow squares). Local airports are marked by the red squares. An example record of an eruption sequence is shown in Figure B, courtesy of Iseul Park, GNS Science. The seismic (black) and acoustic (blue) records compare the data from several eruptions on August 21, 2018 (VUT Time Zone). The eruptions forced the full evacuation of Ambae (Figure C) to neighboring islands of Maewo and Esperitu Santo. This photo is courtesy of Graham Leonard, GNS Science, taken on August 18, 2018. -- Volcano Watch is a weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates.

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Stunning Heights of Lava Fountains in Latest Kīlauea Eruption Episode

Stunning Heights of Lava Fountains in Latest Kīlauea Eruption Episode

Video compilation of Episode 4 of the ongoing Kīlauea summit eruption on January 16, 2025. Three clips show various angles of the erupting lava fountains during the morning of January 16, 2025. USGS Hawaiian Volcano Observatory field crews reported reached heights of 90 to 100 meters (295 to 330 feet) from the north vent and 40 to 50 meters (130 to 160 feet) from the south vent. Courtesy of Hawaiian Volcano Observatory

Ryan Finlay · 4d

Fourth Episode of Kīlauea's Summit Eruption Begins with Lava Fountaining

Fourth Episode of Kīlauea's Summit Eruption Begins with Lava Fountaining

Around 9:15 a.m. HST this morning, January 15, 2025, the eruption of Kīlauea within Kaluapele (summit caldera) resumed with a small lava flow exiting the north vent, following low-level continuous lava spattering that started around 5:40 a.m. HST. from the same vent. Around 9:55 a.m., low-level lava fountaining started with more rigorous lava flow activity. The small sluggish lava flow from the north vent at around 9:15 a.m. today, Wednesday January 15, 2025, marks the beginning of the fourth episode of the ongoing summit eruption. By 9:50 a.m., lava flow activity increased, and lava fountaining began around 9:55 a.m. At time of writing, approximately ten percent of the floor of Halemaʻumaʻu has been covered with new lava, and based on webcam imagery, the lava fountain appears to be 60 meters (200 feet) high. The sluggish, low effusion rate eruptive activity at the start of the fourth eruptive episode was shorter than the sluggish start of second (3-4 hours) and third (2.5 days) eruptive episodes. There are no signs of activity at the south vent. The tiltmeter at Uēkahuna continued to record inflation beneath Halemaʻumaʻu starting around 9 a.m. yesterday, and may be starting to show signs of leveling off. Tremor increased when fountaining began, but is still lower than the first two episodes of vigorous high fountains (>250 feet or 80 meters). If fountaining continues, it is possible that the fountain heights will increase as more gas-rich lava erupted. It is not possible to estimate how high the fountains may get or how long the fountaining will last, but prior episodes have produced fountains over 200 feet high (70 m) that last up to 24 hours. This is the fourth episode of an eruption that began within Halemaʻumaʻu at the summit of Kīlauea volcano on December 23, 2024. Each episode of lava fountaining has continued for 14 hours to 8 days and episodes have been separated by pauses in eruptive activity lasting a less than 24 hours to 12 days. More details are available in the Information Statement that HVO published on January 10, 2025: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2025-01-10T20:11:29+00:00. HVO continues to closely monitor Kīlauea and will issue an eruption update tomorrow morning unless there are significant changes before then. HVO remains in close contact with Hawai‘i Volcanoes National Park and the Hawai‘i County Civil Defense Agency. Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm The Kīlauea summit livestream video is available here: https://www.youtube.com/usgs/live Via USGS Volcanoes

Ryan Finlay · 6d

Paused Eruption at Kilauea Volcano Has Reactivated

Paused Eruption at Kilauea Volcano Has Reactivated

The eruption of Kīlauea volcano that paused through the night, reactivated at several of the vents along the southwest of Halema‘uma‘u crater floor. Eruptive activity remains confined to Halemaʻumaʻu and the downdropped block within the caldera and may fluctuate in vigor over the coming days. No unusual activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone. Seismicity at the summit over the past day has been low with about 8 earthquakes all below magnitude-2.0. At the onset of the eruption yesterday morning, Dec 23, seismic tremor was high. However, around 3 pm yesterday, seismic tremor began to decrease, and currently there is low to moderate tremor related to vent activity. After the summit eruption began, summit tilt meters recorded rapid to moderate deflation until late afternoon. Around 3 pm yesterday, Kīlauea’s summit began slowly inflating. Based on ground instruments, the SO2 emissions were estimated to be over 100,000 tonnes per day during the initial stages of the eruption and dropped to about half of that by mid-day yesterday before the pause. Fountaining decreased abruptly at 3:30 pm yesterday and had ceased by 4:00 pm. Drainback of lava into the original vents began soon after fountaining stopped and continued through the night. Drainback reversed around 8 am this morning, Dec 24, and low-level eruption of sluggish lava occurred from several of yesterday’s vents. Fountains began increasing in vigor around 11:00 am, signaling the onset of a second episode of this eruption. Breakouts of red lava are also visible on the surface of the lava lake as it continues to circulate. A data problem last night resulted in images from Halemaʻumaʻu crater being displayed on a Nāpau Crater camera site. There is no eruptive activity in Nāpau Crater, and the camera has been temporarily taken offline for maintenance. View the Kīlauea summit eruption livestream at: https://www.youtube.com/usgs/live

Ryan Finlay · 1 month ago

New Eruption Has Paused

New Eruption Has Paused

The eruption in Halema'uma'u crater within Kaluapele (Kīlauea summit caldera) that began at 2:20 am HST this morning, December 23, appears to be paused. Throughout most of the day, lava fountained from vents in the southwest portion of the caldera. Initial fountain heights were estimated to be about 260 to 300 feet (80-90 meters) but decreased to about 55 yards (50 m) by 1:00 p.m. Around 3 pm, tilt at the summit stopped showing deflation and seismic tremor began decreasing. By 3:30 pm, lava fountains were barely visible. By 4 pm, fountaining stopped, and seismic tremor was close to background levels. Visible volcanic gas emissions also decreased significantly. The Kīlauea summit livestream video is available here: https://www.youtube.com/usgs/live Lava has covered approximately 650 acres, including all of Halema'uma'u and most of the adjacent downdropped block. The lava is estimated to be about 1 yard (1 meter) thick, giving an estimated average effusion rate of 110 cubic yards per second (85 cubic meters per second) for the first 8 hours of the eruption. Conditions prevented measuring sulfur dioxide (SO2) gas emission rates by normal methods, but nearby monitoring stations estimated over 100,000 tonnes of SO2 per day around 8:00 am and decreasing by half in the early afternoon. These estimates are similar to values measured in the early stages of previous summit eruptions in the past 4 years. HVO continues to closely monitor Kīlauea and will issue an eruption update tomorrow morning unless there are significant changes overnight. USGS photos: A lobe of molten pāhoehoe lava on the floor of Kaluapele (Kīlauea caldera) on December 23, 2024 (photo by M. Patrick). Aerial view from the morning overflight shows the crater floor paved with new rock (photo by M. Zoeller). More Kīlauea photos/video: https://www.usgs.gov/volcanoes/kilauea/photo-and-video-chronology HAWAIIAN VOLCANO OBSERVATORY STATUS REPORT U.S. Geological Survey Monday, December 23, 2024, 5:14 PM HST KILAUEA (VNUM #332010) 19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m) Current Volcano Alert Level: WATCH Current Aviation Color Code: ORANGE Activity Summary: The eruption of Kīlauea slowed significantly between 3:00 and 4:00 p.m. and appears to be paused. The eruption in Halema'uma'u crater within Kaluapele (Kīlauea summit caldera) that began at 2:20 a.m. HST this morning, December 23, continued through most of the day within a closed area of Hawaiʻi Volcanoes National Park. There was no immediate threat to human life or infrastructure, but emission rates of volcanic gases were very high. Webcam imagery and field crew observations showed continued lava fountaining from vents in the southwest portion of the caldera with new lava covering approximately 650 acres, including all of Halema'uma'u and most of the adjacent downdropped block. The area covered so far is a little more than 1 square mile (2.6 square kilometers) and represents about one quarter of the area of Kaluapele. The lava is estimated to be about 1 yard (1 meter) thick, giving an estimated average effusion rate of 110 cubic yards per second (85 cubic meters per second) for the first 8 hours of the eruption. Initial fountain heights were estimated to be about 260 to 300 feet (80-90 meters) and had decreased to about 55 yards (50 m) by 1:00 p.m. Vigorous fountaining produced a plume of volcanic gas and particles that was transported downwind, in a southwest direction over a closed area of Hawaiʻi Volcanoes National Park. Conditions prevented measuring SO2 gas emission rates by normal methods, but nearby monitoring stations estimated over 100,000 tonnes of SO2 per day around 8:00 a.m.and decreasing by half in the early afternoon. These estimates are similar to values measured in the early stages of previous summit eruptions in the past 4 years. Around 3 p.m. today, tilt at the summit stopped showing deflation and seismic tremor began decreasing. By 3:30 p.m., lava fountains were barely visible. By 4 p.m., fountaining had stopped and seismic tremor was close to background levels. Visible volcanic gas emissions have also decreased significantly. These observations indicate that the eruption has slowed significantly and appears to be entering a pause. HVO continues to closely monitor Kīlauea and will issue an eruption update tomorrow morning unless there are significant changes overnight. HVO remains in close contact with Hawai‘i Volcanoes National Park and the Hawai‘i County Civil Defense Agency. Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm The Kīlauea summit livestream video is available here: https://www.youtube.com/usgs/live

Ryan Finlay · 1 month ago

New Eruption Begins Inside Halemaʻumaʻu Crater at Hawaiʻi Volcanoes National Park

New Eruption Begins Inside Halemaʻumaʻu Crater at Hawaiʻi Volcanoes National Park

A new eruption at the summit of Kīlauea volcano is drawing thousands of visitors to Hawaiʻi Volcanoes National Park eager to see new erupting lava by day and the lava glow after dark. This new eruption is viewable from almost all open areas around the caldera. While the park remains open 24 hours a day, some areas may close to protect breeding and nesting nēnē. While an eruption is an exciting experience, keep in mind you are observing a sacred event. The summit of Kīlauea volcano is a wahi kapu (sacred landscape) surrounded with storied places and a delicate ecosystem. The public is reminded to stay safe and help protect park resources by following these precautions: 🌋 Volcanic eruptions can be hazardous and change at any time. Stay on marked trails and overlooks and avoid earth cracks and cliff edges. 🚫 Do not enter closed areas. 💨 Hazardous volcanic gases are billowing out the crater and present a danger to everyone, especially people with heart or respiratory problems, infants, young children and pregnant women. Check the park air alert web page before and during your visit. 🚩 Slow down and drive safely. Expect long waits for parking spaces at popular vantage points like Uēkahuna (formerly the Jaggar Museum) and Devastation Trail parking area. 🐣 Do your part to help protect nēnē by keeping your distance, at least four car lengths away, and never feed nēnē or wildlife. Handouts make nēnē seek out people and cars, putting them in great danger. 🥶 At 4,000 feet, the summit of Kīlauea can be chilly at any time. Bring a rain jacket, wear long pants and closed-toe shoes. Bring a flashlight if visiting at night. So what can visitors expect to see? It depends on when they arrive, and the weather. In the Dark. A magnificent reddish orange glow fills the dark sky. Lava flows have covered much of Halemaʻumaʻu crater floor. The best eruption viewpoints day or night are along Crater Rim Trail, and include Uēkahuna, Kīlauea Overlook, Wahinekapu (Steaming Bluff), Kūpinaʻi Pali (Waldron Ledge), behind Volcano House, Keanakākoʻi and other overlooks. https://www.nps.gov/havo/planyourvisit/eruption-viewing-caldera.htm Image of bright orange lava fountains inside a dark crater at night. NPS photo/Janice Wei

Ryan Finlay · 1 month ago

Hawaii's Pohoiki Boat Ramp Dredging Project in Puna Receives Green Light

Hawaii's Pohoiki Boat Ramp Dredging Project in Puna Receives Green Light

PUNA, HAWAII - After over 6 1/2 years of being closed, final approval for the dredging of the Pohoiki boat ramp has been made. The Hawaii Division of Boating and Ocean Recreation has awarded a dredging contract to Goodfellow Bros. LLC for the restoration of the Pohoiki Boat Ramp facility. The project aims to restore function to the boat ramp, which was severely impacted by the 2018 Kilauea Volcanic Eruption and Earthquakes disaster. During this event, Pohoiki Bay was inundated with volcanic sand, cobble, and boulders, leaving the existing boat ramp landlocked. The restoration project involves creating a channel through the volcanic debris to reconnect the boat ramp to the Pacific Ocean. Approximately 42,000 cubic yards of sediment will be removed through a combination of on-land excavation and mechanical dragline dredging. A portion of the dredged material will be repurposed to fill ponds created by volcanic debris accumulation in the bay's backshore area. The remaining material will be relocated to the main disposal site, which includes the lava land mass that covered the eastern end of the park and adjacent newly accreted land. Work is scheduled to begin in February 2025, with completion anticipated by November 2025, pending final permit approvals which are currently in process. For additional information about the project, interested parties can visit the official Hawaii Department of Land and Natural Resources website at: https://dlnr.hawaii.gov/dobor/fema-final-public-notice-for-pohoiki-boat-ramp-dredging-on-hawaii-island/ More information to come as it becomes available.

Ryan Finlay · 1 month ago