Volcano Watch is a weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates. This week’s article was written by Postdoctoral Researcher David Hyman.

When lava flows break out on the flanks of Kīlauea or Mauna Loa, Hawaiʻi residents and emergency management agencies from all over the world want to know what to expect.

During the 2018 Kīlauea Lower East Rift Zone eruption, lava from 24 fissures inundated more than 8,000 acres (3,200 hectares) of land in the Puna District and more than 700 structures were destroyed. Sobering figures like these highlight the need for forecasting the advance of lava flows to help emergency managers, residents, and USGS Hawaiian Volcano Observatory (HVO) staff. Highly accurate forecasts for other natural hazards such as hurricanes, flooding, drought, and even the spread of vog from Kīlauea are now commonplace. Can we do the same for lava flows?

The most successful forecasting efforts for other natural hazards rely on the ability to simulate flows of water or air. Even though the motion of these fluids is typically much more complex than that of lava, we know a great deal more about water and air than lava as a material. After all, we can’t see inside a lava flow to observe what is happening below the surface the way we can for water and air.

At the heart of hazard forecasts are computer algorithms crunching the numbers as fast as possible to make a relevant forecast. After all, a prediction of severe flooding in 24 hours is not very useful if it takes 23 hours to make that forecast.

Although researchers have been applying the principles of fluid dynamics to lava flows for more than 40 years, most simulations are too slow to use during a crisis when we really want to know the answer to the questions: Where’s that lava headed and when will it get there?

To help answer that question, HVO scientists have for many years forecasted the general path of lava flows using the principle of steepest descent—that lava flows downhill. In many cases, these forecasts have worked really well; however, this method can’t by itself answer the second part: “… and when will it get there?” because it predicts only the route, not the speed or the flow’s final length.

To help answer these questions, USGS scientists are developing a new lava flow forecasting model based around the physics-based simulation of lava as it flows across real topography while cooling and solidifying. This model is designed with simplified, but realistic physics, enabling the simulation of 24 hours of lava advance in as little as a couple of minutes on an ordinary laptop.

This research is supported by the Additional Supplemental Disaster Relief Act of 2019 (H.R. 2157), which has also funded the work of many HVO projects that have been the subjects of recent “Volcano Watch” articles.

Of course, we don’t have perfect knowledge or measurements of our model inputs, so a single simulation doesn’t provide much information about our confidence in a forecast. By running the code many times with a range of inputs, the collection—or ensemble—of all these models can give us a much better idea of the range of possible outcomes. This has been a common practice in forecasting hazardous weather such as hurricanes for many years and is now the cutting edge in volcanic hazards research. HVO scientists are investigating how to produce ensembles using this new model, with the goal of successfully forecasting lava inundation during future eruptions.

Although there is a great deal we do not know about what a volcano is about to do, we can make some short-term forecasts based on what is currently happening. These forecasts, even over short periods of time, give people in the path of lava flows the ability to plan, providing critical answers to the questions: “Where’s that lava headed and when will it get there?”

Join us this next week for two programs about the one-year anniversary of Kīlauea volcano’s summit eruption in Hawai‘i Volcanoes National Park. On Sept. 27 at 7 p.m., an After Dark in the Park presentation by HVO Deputy Scientist-in-Charge David Phillips; and on Sept. 29 at 3 p.m., a “Year on the Edge” talk by a Hawai’i Volcanoes National Park ranger and HVO scientist. Details about these talks are posted on Hawai‘i Volcanoes National Park website at https://www.nps.gov/havo/learn/news/september-2022-events.htm. Email askHVO@usgs.gov for more info.

Volcano Activity Updates

Kīlauea volcano is erupting. Its USGS Volcano Alert level is at WATCH (https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels). Kīlauea updates are issued daily.

Over the past week, lava has continued to erupt from the western vent within Halemaʻumaʻu crater in Hawai‘i Volcanoes National Park. Sulfur dioxide emission rates remain elevated and were last measured at approximately 930 tonnes per day (t/d) on September 21. Seismicity is elevated but stable. At the summit, a brief earthquake swarm and elevated rates of ground deformation occurred on September 20. No unusual activity has been noted along the East Rift Zone or Southwest Rift Zone. For more information on the current eruption of Kīlauea, see https://www.usgs.gov/volcanoes/kilauea/recent-eruption.

Mauna Loa is not erupting and remains at Volcano Alert Level ADVISORY. This alert level does not mean that an eruption is imminent or that progression to an eruption from the current level of unrest is certain. Mauna Loa updates are issued weekly.

This past week, about 190 small-magnitude earthquakes were recorded below the summit and upper elevation flanks of Mauna Loa—the majority of these occurred at shallow depths less than 15 kilometers (9 miles) below sea level. Global Positioning System (GPS) measurements show low rates of ground deformation over the past week. Gas concentrations and fumarole temperatures at both the summit and at Sulphur Cone on the Southwest Rift Zone have remained stable over the past week. Webcams show no changes to the landscape. For more information on current monitoring of Mauna Loa, see: https://www.usgs.gov/volcanoes/mauna-loa/monitoring.

Six earthquakes were reported felt in the Hawaiian Islands during the past week: a M3.4 earthquake 10 km (6 mi) NE of Pāhala at 31 km (19 mi) depth occurred on Sept. 20 at 6:02 p.m. HST, a M2.3 earthquake 5 km (3 mi) E of Pāhala at 33 km (20 mi) depth on Sept. 20 at 5:41 a.m. HST, a M3.4 earthquake 11 km (6 mi) NW of Kalaoa at 43 km (26 mi) depth on Sept. 20 at 5:20 a.m. HST, a M3.2 earthquake 14.1 km (8.8 mi) S of Volcano at 5 km (3 mi) depth on Sept. 17 at 5:19 a.m. HST, a M3.2 earthquake 16 km (9 mi) S of Volcano at 7 km (4 mi) depth on Sept. 17 at 1:39 a.m. HST, and a M3.8 earthquake 46 km (28 mi) S of Lanai City at 14 km (8 mi) depth on Sept. 16 at 6:19 a.m. HST.

HVO continues to closely monitor Kīlauea’s ongoing eruption and Mauna Loa for any signs of increased activity.

Visit HVO’s website for past Volcano Watch articles, Kīlauea and Mauna Loa updates, volcano photos, maps, recent earthquake info, and more. Email questions to askHVO@usgs.gov.

The University of Hawaiʻi at Hilo wants to know what the public thinks of its telescope plan.

The school is proposing to locate its 28-inch educational telescope at Halepōhaku, the mid-level facility on Maunakea. A draft environmental assessment is available for public review and comment.

The proposed project includes a 14-foot high, 18-foot diameter dome that will house the teaching telescope. The dome will be placed on a yet to be constructed wooden deck that will connect to an existing building at Halepōhaku.

The DEA for the UH Hilo teaching telescope anticipates a finding of no significant impact. The deadline to provide comments on the DEA is Oct. 24.

“We hope our local community takes some time to learn more about the teaching telescope and how it will benefit not only UH Hilo students, but the entire island,” said UH Hilo Chancellor Bonnie Irwin. “I am especially excited for the programming ideas that we have for the community at large to utilize the telescope.”

A DEA is required by the Hawaiʻi Board of Land and Natural Resources for astronomy facilities placed within the state conservation district, and it is triggered by the use of state land and funds, UH Hilo stated in a news release.

The public can learn more about the project at an open house on the UH Hilo campus on the first floor of the Science and Technology Building from 5:30-7 p.m. Wednesday, Oct. 5.

The former site of the UH Hilo teaching telescope on the summit of Maunakea is now undergoing decommissioning that is scheduled to be completed in 2023.

When the university submitted a Notice to Proceed in 2016 to decommission the site, more than a dozen community members testified before the Maunakea Management Board (MKMB) and complained about removing the only teaching telescope on the mauna. MKMB ultimately accepted the Notice of Intent in 2021 when the plan to locate the teaching telescope at Halepōhaku was included in the decommissioning plan.

A residential home burned to the ground in Waipi‘o Valley Friday, a scene to which firefighters had difficulty responding given the remote location.

No injuries occurred at the scene after the 30-by-40 single story wooden structure was ravished, the Hawai‘i Fire Department reported on Saturday. Responders were called around 4 p.m. and the fire was out by 5:30 p.m.

Due to the delayed response from thee difficult terrain on the valley floor, chopper 1 units were dispatched to help battle the blaze.

The estimated valued loss wasn’t included and the owner of the structure was listed as unknown on the department’s report.

Waipi‘o Valley is a difficult valley to access and the road into the historical location was recently reopened to county residents in 4-wheel drive vehicles and permitted tour operators after being closed for several months for safety concerns and expected repairs.

Photo Credit: James Grenz

Hilo

Today: Partly sunny with scattered showers. Highs 81 to 86 near the shore to 66 to 73 at 4000 feet. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 66 to 72 near the shore to around 59 at 4000 feet. Light winds. Chance of rain 50 percent.

Sunday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 81 to 86 near the shore to 66 to 73 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 83 to 90 near the shore to around 70 near 5000 feet. Light winds. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers early in the evening. Lows around 74 near the shore to 51 to 57 near 5000 feet. Light winds. Chance of rain 20 percent.

Sunday: Mostly sunny. Isolated showers in the afternoon. Highs 82 to 89 near the shore to around 70 near 5000 feet. Light winds becoming northwest up to 10 mph in the afternoon. Chance of rain 20 percent.

Waimea

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 69 to 89. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows 65 to 72 near the shore to 56 to 65 near 3000 feet. Light winds becoming southeast up to 10 mph after midnight. Chance of rain 50 percent.

Sunday: Mostly sunny with scattered showers. Highs 68 to 88. Northeast winds up to 15 mph. Chance of rain 50 percent.

Kohala

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 69 to 89. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows 65 to 72 near the shore to 56 to 65 near 3000 feet. Light winds becoming southeast up to 10 mph after midnight. Chance of rain 50 percent.

Sunday: Mostly sunny with scattered showers. Highs 68 to 88. Northeast winds up to 15 mph. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Isolated showers. Highs 83 to 88 near the shore to around 68 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy early in the evening then becoming partly cloudy. Isolated showers early in the evening. Lows around 74 near the shore to around 54 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Sunday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 85 near the shore to around 68 near 5000 feet. East winds up to 20 mph becoming 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Puna

Today: Partly sunny with scattered showers. Highs 81 to 86 near the shore to 66 to 73 at 4000 feet. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 66 to 72 near the shore to around 59 at 4000 feet. Light winds. Chance of rain 50 percent.

Sunday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 81 to 86 near the shore to 66 to 73 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny. Isolated showers in the afternoon. Highs 83 to 90 near the shore to 68 to 75 above 4000 feet. Light winds becoming northwest up to 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers early in the evening. Lows around 75 near the shore to 53 to 59 above 4000 feet. Light winds. Chance of rain 20 percent.

Sunday: Mostly sunny. Isolated showers in the afternoon. Highs 82 to 90 near the shore to 66 to 74 above 4000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Gentle southeast flow will continue through the weekend with humid weather and afternoon clouds and showers over interior and leeward areas. A light to moderate trade wind pattern will return around Monday and should become breezy during the second half of next week.

Discussion

High pressure far northeast and low pressure far northwest of the state is producing gentle east to southeast flow across the state this morning. The Molokai plume that developed last evening held on through most of the night with continuous showers from east Oahu and along the Koolau range. The Manoa Lyon Arboretum rain gauge located deep in the Manoa Valley recorded 2.74 inches of rain during the past 12 hours. The plume has finally dissipated this morning, but a few isolated showers and clouds still linger across Oahu this morning.
For today, we will continue to see this hybrid pattern with light east to southeast winds across the state. Daytime sea breezes will cause afternoon clouds and showers across leeward and interior areas through the evening. Any showers that do develop will be slow moving and will be capable of producing some locally heavy rain. With the southeast flow continuing through the weekend, we could very well see the Molokai and Lanai plumes once again over Oahu tonight with some scattered showers across leeward and mountain areas. Humidities will continue to remain high through the weekend with dewpoints around 70 degrees, so temperatures will feel warmer than normal.
Early next week, a weak surface ridge is expected to develop about 150 to 200 miles N of the islands, so we should see a light to moderate trade wind pattern develop. Most showers should mainly be focused over windward areas, but due to the trades being on the lighter side, some brief showers will still be possible over leeward areas due to localized sea breeze development. By the second half of next week, global models are in fairly good agreement with a breezy trade wind pattern across the state.

Aviation

Showers increased in coverage over southern and southeastern portions of Oahu for several hours courtesy of leeward convergence downstream of Molokai. These showers are now quickly diminishing and may bring a brief period of light rain to interior and leeward portions of Oahu early this morning before dissipating altogether. Elsewhere, land breezes are favoring dry conditions and prevailing VFR. Emerging sea breezes this morning into this afternoon will once again favor clouds and showers over island interiors during the peak heating period. VFR is expected to prevail but isolated MVFR will be possible with any heavier showers.
No AIRMETs are in effect.

Marine

A low pressure system far northwest of the islands will continue to weaken the high pressure ridge just north of the state. Expect light to moderate breezes from the east to southeast direction through Sunday. A cold front then stalls north of the region by Tuesday keeping light to fresh easterly breezes in the forecast through the first half of next week. Wind speeds may approach Small Craft Advisory thresholds by the end of next week.
South swell energy will remain elevated through Sunday as another long period swell passes through the region. Once this swell decreases by Sunday night, only background south swell energy will prevail through the first half of next week.
A small north-northwest swell will keep north shore surf elevated today, before fading into almost flat levels on Monday. In the longer term, north shore surf could get another slight boost as a small north-northwest swell arrives on Tuesday and Wednesday.
West facing shores will see a small increase in surf from this long- period south swell and, to a lesser extent, the north-northwest swell. Light trade winds will keep small surf in the forecast along east facing shores through at least next Wednesday.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov