Bardarbunga (Iceland): The eruption continues at similar levels as during the previous days. IMO estimates the volume of lava erupted so far to be at least 200 million cu m, and the surface covered by it 24.5 square km. The lava flows continue to travel eastwards into Jökulsá á Fjöllum river.
At the caldera of Bárðarbunga, subsidence continues at a speed of more than half a meter per day.
“Gas cloud from the eruption drifts to the east. High level of SO2, sulphur dioxide, was measured at Reyðarfjörður last night around 10:00 o’clock. The highest value measured were just under 4000 micrograms per cubic meter. These are the highest values measured in Iceland. High level, 685 micrograms per cubic meter, was also measured in Egilsstaðir.” (IMO)
Slamet (Central Java): Activity at the volcano has increased and VSI raised the alert level to “siaga”, 3 on a scale of 1-4. The mild strombolian activity which had been going on for months at the volcano has become more and more intense since the beginning of September. Some explosions in the past days have been strong enough to eject incandescent material to all over the summit cone of the volcano.
In its latest report on 11 Sep, VSI mentions that 165 eruptions occurred on that day with ejection heights between 50-1500 m.
BNPB, Indonesian’s Civil Protection began preparing for a possible evacuation. According to them, 23,699 people are located within a radius of 5 to 6 km from the summit, and the area up to 4 km radius around the volcano has been declared an exclusion zone.
56,000 dust masks have been distributed to the local population.
Lokon-Empung (North Sulawesi, Indonesia): Small ash emissions along with white steam plumes have occurred again from the volcano recently. At the moment, there is no indications that they have been caused by new magma near the surface, and could be phreatic in nature, or due to disturbance of the hydrothermal system.
Kilauea (Hawai’i): HVO issued the 4th warning status update tonight:
“Between September 10 and 12, the June 27th flow advanced north-northeastward at an average rate of 250 m/day (820 ft/day). By the afternoon of September 12, the flow had advanced approximately 14.9 km (9.3 miles) straight-line distance from the vent, or to within 170 m (560 ft) of the boundary between the Wao Kele o Puna Forest Reserve and the northwest corner of Kaohe Homesteads. At the average rate of advancement of 250 m/day (820 ft/day) since September 10, we project that lava could flow from its current location into the northwest part of Kaohe Homesteads within a day, and to the Pāhoa Village Road (government road) in Pāhoa within 20 days” if there are no major changes.
As seen in the photograph and maps accompanying HVO’s newest release, the lava flow is now at the same elevation as the corner of Kaohe Homesteads, missing it by 170 m (560 ft) and expected to move away downhill. These uphill homes seem to have been spared for now, but as the flow travels further downhill it’s likely to come closer to other houses, with the district of Puna’s biggest village and highway looming 3.1mi (5.0km) below. For now, it’s a tempered bit of good news.
HVO’s latest update:
“The flow front [yesterday at 12:30pm] was 14.8 km (9.2 miles) from the vent, measured in a straight line, and 0.3 km (0.2 miles) from the Forest Reserve/Kaohe Homesteads boundary. The actual length of the flow, measured along the lava tube axis (so that bends in the flow are considered) is 16.9 km (10.5 miles). Between September 6 and 10, the flow front advanced at approximately 400 meters (460 yards) per day. Between September 10 and 11 the advance rate dropped slightly to approximately 300 meters (330 yards) per day. The flow front is still in thick forest, creating smoke plumes as it engulfs trees and other vegetation, but fires are not spreading away from the flow.”
The lava flow’s turn to the northeast this week surprised many online observers, but was not as big a surprise to the scientists at HVO. The blue lines on HVO’s flow update maps indicate the steepest downhill direction calculated from a digital elevation model obtained previously by satellite, but the satellite can’t see the ground beneath the trees. These smaller hidden variations play a significant part in determining a lava flow’s path, and in order to address that HVO scientists run simulations which introduce random variations of about 6 ft (2m) to the DEM surface. Then they compile a probability map based on those simulations. This technique was proven successful during a recent eruption of Mt. Etna, and is now collaboratively being used in Hawai’i. In fact, HVO’s simulations earlier this week showed the current flow path as a good possibility given those random variations, but those maps have not been published online, only presented at the public community meetings.
The flow’s speed has only decreased slightly as well, reflecting the steeper topographic slope of the area and giving the flow a long and narrow geometry. At present the flow width is reportedly 200-300m, which could restrict the lateral damage caused by the lava, at least in the short term. Looking ahead, the longer a lava tube system remains active, the more likely it will produce flows laterally, but for now there’s no reason to believe the lava flow won’t remain narrow as it builds downhill momentum towards the ocean. Along the same lines, there’s no indication that the lava flow will slow down anytime soon and scientists now project it will cross the northern half of Pahoa and the highway around September 24-26.
At the public meeting held at Pahoa High & Intermediate School last night, officials presented the latest lava flow maps and projections following the flow’s unexpected turn towards Pahoa town two days ago. HVO scientists reported that the steep slope has allowed to flow to continue moving quickly and that the new path puts it directly through the town of Pahoa in the range of 13-15 days.
Residents were offered the latest science, logistics concerning evacuation and possible disruption of services, and a prayer reminding that people’s greatest resource is each other. Hawaii County Mayor Billy Kenoi drew the loudest applause when announcing that construction has already started on two alternate access roads into the area, but the mayor reminded residents that once the flow crosses the first highway it will continue downhill and eventually cut off these other, under construction routes as well. The mayor then announced plans to repave the Chain of Craters Road from within the National Park to Kalapana despite the great expense and lack of county funds, with the hope that assistance will come from the state or federal level. The county is going as far as scrapping construction on a children’s playground in Pahoa in order to relocate those contracted workers to road construction.
The mayor also stated that lessons learned from Tropical Storm Iselle will be put to use, prioritizing uninterrupted power service, telecommunication and road access as the key components for all other concerns, including health care, postal service and bus service. The county is establishing a crisis center at the Pahoa Community Center within 72 hours and discontinuing public meetings, although an information fair is being held tomorrow to connect residents to service providers including banks, insurance, police, fire, water, power, moving & storage, health care, legal advice and transportation.