Multi-Hazard Mitigation Plan: 08. Lava And Vog

Home

Chapter 8:Hazard Analysis—Lava and VOG toxic at excessive levels of consumption. Recent surveys of domestic catchment systems in the area of HOVE and Volcano have shown that plume constituents are contributing chloride, sulfate and fluoride ions to catchment waters. HOVE water samples showed the higher concentrations of these ions, by factors of four to ten above those of Volcano, and reflect a higher integrated exposure to plume deposition than did the Volcano community. (The higher rainfall rates and flow through the catchment systems in Volcano is also likely to contribute to the lower values there.) The median values of all ions for both communities were considerably lower than drinking water standards but some samples from both the HOVE and Volcano areas did show values that were substantially higher than the median values and were much closer to drinking water limits. Hence, significant changes in the plume discharge rates or in weather patterns could warrant further monitoring of the catchment systems. Of potentially greater concern is the deposition of fluoride salts onto forage crops. The scientific literature has documented a number of events where sheep, cattle, and horses have suffered significant losses as a result of both acute exposure as well as chronic exposure and accumulation of fluoride salts by grazing animals. Although there have been a few anecdotal reports of symptoms of fluorosis by some ranchers on the Big Island, further investigations will be necessary to determine whether the forage crops are accumulating sufficient fluoride to be of concern in the downwind communities. 8.1.2.1.2 TEB Vent and Pu'u O'o The TEB vent, located on the Kilauea East Rift Zone (KERZ), is discharging gases similar to those at Halema'uma'u, albeit at different relative concentrations. Due to the dynamics of gas release from magma, the relative amount of carbon dioxide to sulfur dioxide is lower at the TEB vent than at Halema'uma'u and the concentrations of HCl and HF are somewhat higher. This discharge is also likely to have lower amounts of sulfur trioxide and hydrogen sulfide than the summit discharge. The sulfur dioxide emission rates from TEB Vent have ranged as high as 2000 tonnes per day but currently are in the range of 1000 tonnes per day or somewhat less. The chemical processes occurring in the TEB plume, are in most respects, identical to those occurring in the Halema'uma'u plume but, because of the vent's location on the KERZ, the trajectory taken by the plume (during normal trade wind conditions) is substantially different from that of the former. Whereas the Halema'uma'u plume is often affected by the upslope winds generated by daytime heating of Mauna Loa's flanks, the TEB plume is far enough off-shore that it only rarely affects the south-east flank of Mauna Loa. However, the TEB plume has shown a history of becoming trapped in the eddy system on the southwest and western flank of Mauna Loa and has consistently affected air quality on the Kona side of the island since the initiation of the Pu'u O'o eruption in 1983. With the onset of the Halema'uma'u eruption, the addition of its plume to that of TEB has produced further deterioration in the Kona air quality. 8-7 Hawaii County Multi-Hazard Mitigation Plan