- Current Update, last updated May 11, 2015 12:15 :
Monitoring data through the month of April 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 200 located earthquakes occurring in April. Though there were no swarms on the west flank of Mauna Loa, earthquake rates remained above background with approximately 13 earthquakes occurring in April. All earthquakes in the past month have been small relative to earthquake sequences observed before eruptions in 1975 and 1984.
Deformation: The pattern of motion of continuously recording GPS stations in April indicates that inflation continues. Velocities were similar to the average rates measured since the start of the current inflationary period in mid-2014. The pattern and rates are very similar to those observed in mid 2004-mid 2005, which, along with a short period in 2002, had been the time of highest observed velocities since GPS monitoring started in the mid-1990's.
Gas: No significant changes in SO2, CO2 were recorded by the Mokuaweoweo gas and temperature monitors during April. Beginning around 03 April, fumarole temperature rose from ca. 79.5 deg C to approximately 83, by the end of the month. This the second such significant positive excursion since the station was installed in 2005, and the highest temperature recorded by the fumarole monitor, thus far. The last temperature event began in September 2014, with a low of 72.5 deg c, peaking at 79 deg in late November, before declining to 77 degrees in January.
- 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