- Current Update, last updated Sep 4, 2014 12:06 :
Seismicity continued to be slightly elevated; deformation patterns may suggest renewed inflation.
Monitoring data through the month of August 2014:
Seismicity: Seismicity at Mauna Loa remains elevated in several parts of the volcano. In early August a swarm of Deep (45-50 km) Long Period (DLP) earthquakes occurred under the volcano. It was the most numerous swarm of earthquakes in this region since a swarm of DLP earthquakes and deformation in 2004 and 2005. It is common at Mauna Loa and other volcanoes worldwide to associate deep magma intrusion with the occurrence of DLP earthquakes. Earthquake rates on the Upper Southwest Rift Zone (Sulfur Cone) and West Flank remain elevated, though similar to the past couple of months. Seismicity rates in the Mokuʻāweoweo Crater increased over previous months with at over 20 events in the past month at shallow (<2 km) depths. All earthquakes in the past month have been small relative to earthquake sequences observed before eruptions in 1975 and 1984.
Deformation: GPS data show a broad pattern of horizontal displacements suggesting renewed inflation, with the majority of the volume accumulating in a dike-like body beneath the caldera. InSAR is starting to show the double-lobed pattern typical of dike widening. Reinflation may have started in April or May of this year. Displacement rates in August were a little more than half those measured during the height of the 2002-2009 inflation in 2004-2005.
Gas: Instrumentation was not functional during the month of August.
- 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