Volcano Information
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Mauna Loa
- Current Update, last updated May 9, 2012 08:19 HST:
Mauna Loa is not inflating. Seismicity rates were low.
Deformation: is occurring at slow rates, dominated by southeasterly motion of the southeast flank. If any inflation is occurring, it is at a very low rate. Upgrades of many Mauna Loa sites in late 2011 produced some apparent data offsets that will be corrected once a longer post-upgrade time series is available for analysis.
Seismicity: There was no unusual seismicity. HVO seismic networks detected 1 event below summit area, 4 events to the north and west of the summit, 10 shallow events within the upper southwest rift, and 1 shallow and 1 deep M3.3 event on the NW rift
Gas: The high values being recorded for SO2 on the Mokuaweoweo gas monitor continued during April. As it was in March, other sensors-- Fumarole temperature, and CO2-- did not show a corresponding change, so we continue to suspect that the anomalous SO2 values reflect a failing sensor rather than a real change in SO2 at the site. Scheduling conflicts during the month prevented us from replacing the SO2 sensor, but this still remains the plan. Otherwise, ambient CO2 indicated routine diurnal variations. Fumarole temperature posted an approximately 3 degree range during the month-- normal for this location.
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
Latitude: 19.475
Longitude: -155.608
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
