Report on Kilauea (United States) — 9 July-15 July 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 9 July-15 July 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Kilauea (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 9 July-15 July 2014. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
During 2-14 July HVO reported that the circulating lava lake occasionally rose and fell in the deep pit within Kilauea's Halema`uma`u Crater. The lava-lake level fluctuated between 30 and 45 m below the Overlook crater rim; on 13 July, the level dropped 45-50 m during periods of spattering. Weak inflation was measured at the summit during 2-8 July, deflation during 9-10 July, no significant deformation during 11-13 July, and slight inflation on 14 July. Gas emissions remained elevated; during the weeks ending on 1 and 8 July, the summit SO2 emission rates were 3,800-8,400 tonnes/day and 5,800-6,900 tonnes/day, respectively. Earthquakes during 2-7 July (11-21/day) and 8-14 July (5-27/day) were strong enough to be located beneath Kilauea. The plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas; smaller particles may have been dropped several kilometers away.
On 3 July, the total SO2 emission rate from all East Rift Zone sources was 500 tonnes per day. During 2-14 July, four lava ponds within cones occupied the crater floor of Pu`u`O`o. The vent which opened on the NE flank of Pu`u`O`o on 27 June remained active and supplied a flow extending NE, constructing a lava shield that continued to expand until 10 July. This new flow cut off lava supply to the Kahauale`a 2 flow, which by 3 July was no longer active. The new shield developed a perched lava pond which crusted over and became quiescent when the pond spilled over on 11 July. Lava continued to erupt from the base of the structure, supplying flows that accumulated around the flat-lying terrain at the base of Pu`u`O`o until 14 July. Continuous deflation was measured at Pu`u`O`o.
Geologic Background. Kilauea, which overlaps the E flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 km2, destroying nearly 200 houses and adding new coastline to the island.