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Home My WebLink AboutCOM 0560.000 2018-2020 J Z�..oir Maile Medeiros David o,`'.Y �' Phone: (808) 323-4277 Council District 6 ° ''�' Fax: (808) 329-4786 Portion N. S. Kona/Ka`u/Volcano * r Email: maile.david@hawaiicounty.gov a°- 4rF SOF NPdi HAWAII COUNTY COUNCIL County of Hawai`i West Hawai`i Civic Center, Bldg. A 74-5044 Ane Keohokalole Hwy. - Kailua-Kona, Hawai`i 96740 DATE: October 17, 2019 _ TO: Aaron Chung, Council Chair And Members of the Hawaii County Council r FROM: �~ vlaile David, Council Member Council District 6 SUBJECT: U.S. Geological Survey/Civil Defense Presentation regarding the water lake in Halema`uma`u Crater I hereby request 45 minutes for a presentation by the U.S. Geological Survey and Civil Defense relating to the source and accumulation of water within Halema`uma`u Crater. Please place on the appropriate committee for our Hilo Committee Meetings scheduled for November 5, 2019. Mahalo a nui loa. MD/dmm cc: Laura Murashige Comm. N Serving the Interests of the People of Our Island Ref. To: Hawaii County Is an Equal Opportunity Provider And Employer Ref. 1)ate OCT 2 2 2019 Water IaI<e int e Halema ' uma ' u crater November 5, 2019 Presented by Tina Neal Prepared by Matt Patrick and Jim Kauahikaua : USGS science/or a changing world Recent airborne image of Halema`uma`u e we �� •�._� .may., '«{� , s 37 � i� p _ r i, ,'; ?x "0 USGS J �n t r « «s, 0 10� �M4 .,t,. science/or a changing world Recent view from the west caldera rim a w x r � I � s. y at S.. is a� US G S =° a.a science/or a changing world Water pond first observed July 25 Timelapse sequence: August 6-September 8 F' 'Aj6, ro p � s o- - y + r <10 m (33 ft) wide .I ,.... � .. rte'N .� -._ - - ♦ M1. - .�._... 'pC r. i' rM 58 m (190 ft) u, _ a Water level is rising gradually, suggesting w groundwater seepage, not surface runoff 15 { 40 feet deep 10 4-1 , MIR-.MIN.- I (D E 15 cm/day Q - 6 inches/day 7 _ a , 5 0 I 07/31 08/14 08/28 09/11 09/25 10/09 10/23 Date (MM/DD) in 2019 � USGS September • science/or a changing world Before 2018: Lava lake phase Keller well Halema`uma`u lava lake water table water table � "steam sleeve" X41 not to scale USGS science for a changing world After 2018 eruption: water table begins to seep back Keller well Halema`uma`u 600 m (-2000 ft) r not to scale Mi USGS science for a changing world Now: water table is at bottom of Halema`uma`u Keller well Halema`uma`u water table water pond not to scale : USGS science for a changing world Coming months: continued rise to equilibrium Keller well Halema`uma`u water pond water table not to scale : USGS science for a changing world Nearby water table elevation is about 65 m (210 ft) higher than current pond level Water level in pond might be able to rise this high a: USGS science for a changing world The water pond is hot, and heated by the magmatic system E!3 I �II 7II �ry s I �fl i vfl �!I 15HC Water surface temperature is about 70 C (158 F) — consistent over past month ` U S G S science for a changing world No detectable signs of imminent unrest at the summit • Currently, the water pond is stable, with a slow and consistent rise in water level, and no obvious changes in color or surface activity • Ongoing inflation indicates that the summit magma chamber continues to steadily recharge, and magma remains deep in the system • Low rates of SO2 emission (45 tonnes per day), but some sulfur is being absorbed by the pond (and groundwater) • Seismicity is elevated (compared to pre-2018) but has been relatively steady in recent months : USGS science/or a changing world Implications for hazards At Kilauea and many other volcanoes, magma interacting with water can trigger explosive activity ?� y4 R F Ej( ' , �,. 18 Spa /l� t1 � i � 4A / F4 r� �' .yl�•. _�, �_,�� .fit io <>a ► d •T t= _•ki x3aaB �1 �� . g p_ try RIM,: - y "J .50-74 i \ Figure 2:Projectile Zone for the 1924 eruption at Kilauea. Dots are individual projectiles between X25 and >150 cm in diameter Collectively, they define a hazard zone of extreme risk with a radius of approximately 1 km (0.6 miles). Orange color indicates post-1924 lava flows, which bury any earlier ballistic rocks. Ballistic rocks fell in the white area just southeast of the crater but cannot be distinguished ' USGS today from older rocks owing to human activity after 1924. science/or a changing world Implications for hazards 0.8-1 .6,,' 00uter isopach, 5 cm G i 0.2-0.7 f' 0.3-0.4 0 10 kilometers "mere-film" 9 11 J Figure 3:Ashfall Zone for 1924. The red line encloses the large and complex region of ashfall. Numbers are thicknesses measured by Thomas Jaggar soon after the 1924 eruption. Units are centimeters. We know that in fact the Ashfall Zone was much larger than indicated here as reports indicate that ash was dispersed northward, as far as North Nilo. An isopach is a line of equal ash thickness. ` UsGs science for a changing world Implications for hazards • In Kilauea's geologic record, there is a long history of larger explosions at the summit, that affected the entire summit region. • Some of these explosions are thought to be triggered by rapidly rising magma interacting with surface water, but the exact conditions that produced the explosive behavior are not clear H - _ _ 3 : USGS science for a changing world Implications for hazards • Most likely, explosive activity would be preceded by detectable precursors, such as rapid inflation, or increased seismicity, that indicates magma rising • However, small gas-driven explosions can occur at volcanic lakes without warning and cannot be ruled out : USGS science/or a changing world HVO monitoring of the water pond and summit Webcam monitoring Near-daily water level measurements Regular thermal measurements 55 45 f z 40 . s L B30 A y F - 3`C io Near-daily visual observations Routine overflights Seismic, deformation, gas monitoring 1 4 71, m -- USGS science fora changing world Direct water sampling is being planned r �y 9, y ilfr�J l; 1 x S • Water chemistry will tell us the origin of the water, and how much sulfur is being absorbed by the pond • It will provide a chemical baseline to compare against any future changes ` USGs science for a changing world