- Current Update, last updated Dec 5, 2014 10:02 :
Seismicity continued to be slightly elevated; deformation patterns may suggest renewed inflation.
Monitoring data through the month of November 2014:
Seismicity: Earthquake rates on the Upper Southwest Rift Zone (Sulfur Cone) remain elevated, with slightly stronger earthquakes than seen in previous months. Seismicity rates in the Mokuʻāweoweo Crater remains elevated with approximately 50 very small events in the past month at shallow (<5 km) depths. There were approximately 15 earthquakes in the past month on the west flank of Mauna Loa. All earthquakes in the past month have been small relative to earthquake sequences observed before eruptions in 1975 and 1984.
Deformation: GPS data continue to show a broad pattern of displacements suggesting inflation of one or more magma reservoirs, with the majority of the volume accumulating in a dike-like body beneath the caldera and upper SW rift zone. Displacements continued at the same average rates measured since the increase in rates in late June/early July.
Gas: No significant changes in SO2, CO2 were recorded by the Mokuʻāweoweo gas monitor. Notably though, we have continued to observe an increasing fumarole temperature. As discussed last month, this temperature increase, while numerically small, deviates significantly from the seasonal trend observed at this site since fumarole temperature began in 2005. Between the beginning of October and the beginning of December, this average temperature increased from ca. 72 deg C to 79 deg C. The major portion of this change occurred between 11/1 and 11/21.
- 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