Mauna Loa

Volcano number:332020
Region:Hawaii and Pacific Ocean
Country:United States
Geodetic measurements?Yes
Deformation observation?Yes
Measurement method(s):InSAR, GPS - continuous, Tiltmeter
Duration of observation:1995-present (GPS), 2000-2010 (InSAR)
Inferred cause of deformation:Magmatic, Faulting/tectonics
Characteristics of deformation:

Mauna Loa is currently in its longest period of repose in the last 200 years, with its last eruption occurring in 1984. However there was an observed increase in seismicity beginning in March 2013 with a slow inflation starting in early 2014. As of July 2014, InSAR and GPS data indicate subtle inflationary deformation, although inflation rates are a lot less than those observed before and after the 1984 eruption. These rates are also far less than during the 2002-2009 unrest. (Thelen et al., 2014).

The inflation is consistent with pressurisation of the known 3-5 km deep magma storage area beneath Mauna Loa’s caldera.  (Thelen et al., 2014).

InSAR studies covering the period between 2002 and 2005 suggest a  depth to the magma chamber of 4.7 km below the summit, with a radius of 1.1 km, and a dike intrusion at 4-8 km depth and 8 km length. (La Marra et al., 2015).

The summit area of Mauna Loa has undergone a long term inflation between 2003 and 2014, with a peak of about 8 cm of vertical deformation between mid-2004 and mid-2005, especially on the summit. Part of this deformation may be related to the instability of the flank. La Marra et al. (2015) identified several distinct periods with linear deformation behavior. (La Marra et al., 2015).

Reference:Thelen, W.A., Poland, M.P. and Miklius, A., 2014, December. Seismic and Geodetic Observations of Recent Unrest at Mauna Loa Volcano. In AGU Fall Meeting Abstracts (Vol. 1, p. 07).
Reference:La Marra, D., Poland, M., Miklius, A. and Acocella, V., 2015, April. SBAS-InSAR analysis of a decade of surface deformation at Mauna Loa (Hawai'i): Preliminary results. In EGU General Assembly Conference Abstracts (Vol. 17, p. 928).
Location:-155.608, 19.475