Kaʻū News Briefs, Friday, February 8, 2019

     Last year, a collaboration between OED, the BBC, and Forward Arts Foundation to find and define local English words resulted in the expansion. OED is widening its search to English speakers around the world, with associate editor Eleanor Maier calling the early response "phenomenal."

     "Regional words indicate that their users come from a particular place and often contribute to one's sense of identity," said Maier in an interview with The Guardian. "The OED aims to cover all types of English, including standard English, scientific and technical vocabulary, literary words, slang, and regionalisms. So it's important to include these words to enable us to present a picture of the English language in all its forms."

     Maier wrote online that the word's origin was unknown, but it could be related to the Hawaiian word for inept, "hemahema," and possibly combined with Pidgin "junk," meaning "bad." She says the earliest example of "hammajang" was in a short story published in 1988.

     Geology of the past, how long will the eruption last?

     The 2018 lower East Rift Zone eruption of Kīlauea brought an end to the 35+ year eruption at Pu‘u ‘Ō‘ō. With the draining of the summit and the collapse of Pu‘u ‘Ō‘ō, Puna residents were concerned that the eruption in the LERZ could be long-lived.
     Fissure 8 reactivates in late May and becomes the dominant vent in the LERZ eruption.

Fissure 8 reactivates in late May and becomes the dominant vent in the LERZ eruption. USGS photo

     How could we evaluate, at that time, how long the eruption would last? Geologic investigations work under the premise that the key to the future is found in the past. By investigating past eruptions, we learn the way a volcano is likely to behave in the future.
     We looked at the geology of Kīlaueato see what we could learn about past eruptive behavior. Along the east rift zone are features, such as lava shields, that are indicative of long-lived eruptions. These include Maunaulu, Kānenuiohamo, Pu‘u ‘Ō‘ō, Kupaianaha, and Heiheiahulu (above the Black Sands subdivision). These all occur in the upper and middle parts of the East Rift Zone. Where are the lava shields in the LERZ? There are none.
     Large cones reveal past eruptions along the LERZ, but most of the eruptive vents are small and are hidden by the lush vegetation. All the cones and fissure vents erupted flows of only limited extent and are small when compared to the flow fields created by the shields.
     The limited extent of the flows infers that the eruptions lasted for a relatively short period of time – but how short? Adopting a broad perspective, we analyzed how past eruptions could guide us to estimate how long the 2018 eruption could last.
     Using historical information from LERZ eruptions in 1840, 1955, 1960, and 1961, we were able to calculate the average eruption rate (or flux) from the volume and duration. The flux values for 1840, 1955, 1960, and 1961, respectively, are 91, 12, 36, and 8 cubic meters per second. How does this information help us assess prehistoric eruption characteristics?

Puʻu ʻŌʻō from the north rim today, at about noon. USGS HVO scientists report clouds seen rising from the crater  are probably rockfall plumes. USGS photo from webcam

     For prehistoric eruptions where we lacked information on eruption rate and duration, we compiled lava flow areas. To estimate the volume of erupted material, we compiled the mappable area, estimated how much more area may have been covered by later flows, and finally multiplied the "corrected" area by an average thickness of 7 m (23 ft), based on drill hole data.
     For flow area correction, we assumed that flows 200-400 years old had 25% of the original flow buried by younger flows and that flows 400-750 years old had half – 50% – of their original surface covered.
     Why do we need the corrected volume of the prehistoric flows? We can use the volume of the prehistoric flows to provide constraints on eruption duration. To do this, we divided the correct prehistoric flow volume by a range of historic fluxes to arrive at the duration – the number of days – the prehistoric eruptions could have lasted.
     In our analyses, we threw out the high and low flux values and used the intermediate values to calculate the eruption duration. Why discard the highest and lowest effusion rates? By the time we conducted this assessment, the 2018 eruption had already been going on for almost one month and the shortest eruption (1961) lasted only one day and the highest rate resulted in duration of about 20 days. Using the flux information from the 1955 and 1960 eruptions, we calculated an eruption duration range of 51 to 155 days. The 2018 eruption lasted 124 days.

Mauna Loa's Mokuʻāweoweo Caldera, from the south rim  today, remains quiet. USGS photo from webcam

     Although we could not discount that the eruption may last for years, this geologic look at prior LERZ eruptions – along with the absence of shields, the modest flow fields, and the smaller eruptive volumes of prior events – all point to activity of limited duration. By using prehistoric geologic information garnered from geologic mapping, the key to the future was to look at the past; our analysis provided a valuable guide on how long the 2018 eruption would last.

     Kīlaueais not erupting. Rates of seismicity, deformation, and gas release have not changed significantly over the past week.
     There were 2 events with 3 or more felt reports in the Hawaiian Islands during the past week. On Feb. 4 at 7:40 p.m., a magnitude-2.6 earthquake occurred 11 km (7 mi) northwest of VolcanoVillage at a depth of 9 km (5.8 mi) below sea level. On Feb. 7, at 9:06 a.m., a magnitude-4.6 earthquake occurred offshore 85 km (53 mi) southwest of Hawaiian Ocean View at a depth of 27 km (16.7 mi) below sea level.
     Deformation signals are consistent with refilling of the middle ERZ. Sulfur dioxide emission rates have been below detection limits in the lower ERZ since early September, though minor amounts of volcanic gas are still present.
      Hazardous conditions still exist at both the lower ERZ and summit. Residents in the lower Puna District and Kīlaueasummit areas on the Island of Hawai‘i should stay informed and heed Hawai‘i CountyCivil Defense closures, warnings, and messages, hawaiicounty.gov/active-alerts.
     USGS Volcano Alert level for Mauna Loa remains at NORMAL.

VERY STRONG WINDS, AND POSSIBLE COASTAL FLOODING THIS WEEKEND, predicts the National Weather Service, which issued another statement today for the entire Kaʻū region, from the coast to the summits of Mauna Loa and Mauna Keavolcanoes. The alert is for much of the state:

     "An unusually strong storm system will move toward the islands from the north over the weekend, bringing with it multiple weather hazards. The storm will send a powerful swell toward the islands that will impact exposed north and west facing shores with very high surf.

     "Additionally, the combination of strong onshore winds and high surf will increase the potential for significant coastal flooding that could lead to property damage, road closures, and beach erosion.

     "The storm system will also bring strong and potentially damaging north to northwest winds to the island chain, particularly Saturday night through Sunday evening. While these winds are expected to be strongest over ridges and mountaintops, they will also accelerate downslope, impacting heavily populated areas. In addition, intense, fast moving rain showers or squalls may bring very strong and damaging winds as the storm makes its closest approach.

     "If you have outdoor plans for the weekend, be prepared for very windy conditions. If your plans include marine activities, you may want to consider postponing them."

     Trojans Boys Basketball travel for their HHSAA Division II tournament on MauiFeb. 21 through 23. They are fundraising with an invitation tournament Friday, Feb. 15. See below for more details.