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Volcano Watch: Learning from the Impact of the 2018 Kīlauea LERZ Lava Flows : Maui Now

by scientists and affiliates of the US Geological Survey Hawaiian Volcano Observatory. This week’s article was written by Elinor Meredith, a PhD student at the Earth Observatory of Singapore.

Lava flows erupted from Kīlauea’s lower East Rift Zone in 2018, devastating the lower Puna. In 2019, a team of scientists from the USGS, the Earth Observatory of Singapore and GNS Science in New Zealand set out to document and assess the impacts on buildings and infrastructure to improve understanding of how lava flows affect the built environment affect.

With permission from local residents, we visited properties along the lava flow margins to meet local residents, take photos, and note the severity and type of damage to buildings. In addition to field visits, we evaluated more than 8,000 photos taken by USGS scientists before, during, and after the eruption. These photographs, together with satellite imagery, form the world’s largest available data set of lava flows.

We used our data to develop the first set of damage states for lava flows. Damage states are classifications of structural damage on a scale ranging from minor damage to major damage and destruction, and are often used to categorize buildings damaged by other hazards, such as hurricanes or earthquakes. This new set of damage states allowed us to classify all structures in the area by damage severity. Severity ranged from no visible damage, minor melting of plastic from heat, corrosion of metal from gases, to complete burial.

Sources/Usage: Public Domain.
Building damage states used to classify buildings affected by the 2018 Lower East Rift Zone lava flows of Kīlauea by damage severity, first developed for lava flows. (Source: Elinor Meredith and Nguyen Thi Nam Phuong/Earth Observatory of Singapore).

The damage classification included all types of structures, including houses, water tanks and other agricultural or industrial buildings. The 2018 Kīlauea lava flows, which inundated 14 square miles (35.5 square kilometers) of land, destroyed a total of 1,839 and damaged 90 buildings. This is the highest recorded number of affected structures from a lava flow event in Hawaii and one of the highest in the world. Later in 2021, lava flows demolished 2,896 buildings on La Palma, Spain and destroyed 3,629 homes, 12 schools and 3 health facilities on Nyiragongo Volcano, Democratic Republic of the Congo.

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The damage severity on each structure was related to the lava thickness. The data showed that increased lava flow thickness was generally associated with greater damage severity, up to 2 m (6.6 ft), after which all buildings were destroyed. However, when the flow thickness was less than 2 m (6.6 ft), there was a range of severity of damage along the edges of the flow. In particular, round and metal water tanks were resistant to these thinner currents. There were similar results for the circular structures at Chã das Caldeiras, Cape Verde, during the 2014-2015 Fogo Volcano lava flows, where circular masonry buildings resisted destruction along the river edges. During these lava flows, 170 structures were destroyed and 90 structures damaged.

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Aerial view of Kīlauea’s Lower East Rift Zone lava flows in 2018 that inundated 14 square miles (35.5 square kilometers) of land, damaging and destroying structures. USGS photographs like this one were used in our lava flow impact assessment.

We found that the structures were damaged primarily in the first four weeks of the 14-week 2018 eruption while the main lava channels were emplaced. Many other structures not originally affected were destroyed by later lava flows that erupted from or overtopped the main lava channels.

We note that some houses in kīpukas survived and were classified as not damaged at all or less damaged. However, these homes have been severely affected by lack of access and disruptions to supplies. We have also seen effects on homes from fissure fumes and gases months after the eruption ended.

One of our key findings is that damage has been recorded up to nearly 600 m (2,000 ft) away from the lava flow, likely from secondary processes such as the spread of fire facilitated by the dried vegetation downwind of the lava channels. This finding suggests that combustible materials on or near properties may cause damage beyond the lava flow.

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Recently published in the Bulletin of Volcanology, this work emphasizes that damage from lava flows can occur beyond the main lava flow itself, particularly from later erupting lava flows and channel overflows, or from secondary fires. Findings from this research contribute to the global empirical dataset of lava impacts and will be used to inform future lava flow damage assessments in Hawaii and beyond.

Volcano activity updates

The Kīlauea volcano erupts. His USGS Volcano Alert Level is WATCH and is issued daily.

Lava has continued to erupt from the western vent in Halemaʻumaʻu Crater in Hawaii Volcanoes National Park for the past week. Sulfur dioxide emission rates remain elevated and were last measured on November 15 at about 500 tons per day (t/d). Seismicity is elevated but stable, with few earthquakes and ongoing volcanic shocks. Last week, peak inclinometers recorded a deflation-inflation (DI) event.

Mauna Loa is not erupting and remains on 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 concern is certain.

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In the past week, about 300 low-magnitude earthquakes were recorded below the summit and upper flanks of Mauna Loa – most of them occurring at shallow depths, less than 15 kilometers (9 miles) below sea level. Global Positioning System (GPS) measurements show ongoing ground deformation consistent with the bulging of a magma chamber beneath the summit. Gas concentrations and fumarole temperatures at both the summit and Sulfur Cone in the Southwest Rift Zone have remained stable for the past week. Webcams do not show any changes in the landscape.

In the past week, there have been 5 events with 3 or more felt messages in the Hawaiian Islands: a M3.9 earthquake 5 km (3 miles) SSW of Pāhala at 31 km (19 miles) depth on November 16 at 6:00 p.m.: 56 p.m. HST, a M2.2 earthquake 3 km (1 mi) S of Volcano at 2 km (1 mi) depth on November 13 at 22:50 HST, a M3.2 earthquake 15 km (9 mi) ENE of Honaunau-Napoopoo at 4 km (3 miles) depth on November 12 at 3:10 p.m. HST, a M3.7 earthquake 18 km (11 miles) ESE of Nāʻālehu at 35 km (22 miles) depth on November 12 at 10:44 a.m. HST and an M3.6 earthquake 9 km (5 miles) east of Pāhala at 31 km (19 miles) depth on November 11 at 10:29 a.m. HST.

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

Volcano Watch is a weekly article and activity update written by scientists and affiliates at the US Geological Survey Hawaiian Volcano Observatory.

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