- Current Update, last updated Jun 5, 2015 08:20 :
Monitoring data through the month of May 2015:
Seismicity: Seismicity at Mauna Loa remains elevated in several parts of the volcano. Earthquake rates on the upper Southwest Rift Zone (Sulfur Cone) and Mokuʻāweoweo Crater remain elevated, with nearly 250 located earthquakes occurring in May. Though there were no swarms on the west flank of Mauna Loa, earthquake rates remained above background with approximately 25 earthquakes occurring in May. All earthquakes in the past month have been small relative to earthquake sequences observed before eruptions in 1975 and 1984.
Deformation: The Mauna Loa GPS network recorded very little deformation associated with inflation during May. Temporary lulls in inflation, lasting weeks to more than a month, have been common since reinflation started in mid-2014. Slow, southeasterly motion of the southeast flank, which has been observed ever since we have had the ability to measure it in the mid 1990s, appears to have continued through the month.
Gas: No significant changes in SO2 and CO2 were recorded by the continuous fumaroles monitor during May, 2015. The positive fumarole temperature excursion, from 75 to 82 degrees, reported last month, reversed beginning about 08 May, producing a downward trend through month’s end, to about 80.5 degrees.
- Volcanic History Overview: Massive Mauna Loa shield volcano rises almost 9 km above the sea floor to form the world's largest active volcano. Flank eruptions are predominately from the lengthy NE and SW rift zones, and the summit is cut by the Mokuaweoweo caldera, which sits within an older and larger 6 x 8 km caldera. Two of the youngest large debris avalanches documented in Hawaii traveled nearly 100 km from Mauna Loa; the second of the Alika avalanches was emplaced about 105,000 years ago (Moore et al. 1989). Almost 90% of the surface of the basaltic shield volcano is covered by lavas less than 4000 years old (Lockwood and Lipman, 1987). During a 750-year eruptive period beginning about 1500 years ago, a series of voluminous overflows from a summit lava lake covered about one fourth of the volcano's surface. The ensuing 750-year period, from shortly after the formation of Mokuaweoweo caldera until the present, saw an additional quarter of the volcano covered with lava flows predominately from summit and NW rift zone vents.
- Location: Hawaii and Pacific Ocean, HI
Elevation: 4170 m
Recent Eruption: 1984
- Hazard Assessments: Mullineaux, Donal Ray; Peterson, Donald W., 1974, Volcanic hazards on the Island of Hawaii, Open-File Report 74-239.
- Link to monitoring data: Recent Earthquakes in Hawaii Page
Volcanic Alert Level: NORMAL Aviation Color Code: GREEN