Mauna Loa: A Decade Volcano

by J.P. Lockwood and J.M. Rhodes.

The reference for this publication is Periodico di Mineralogia (Rome), 44, 45-47, 1995.

The paper was presented as part of the Decade Volcano Symposium at the IAVCEI Conference, Volcanoes in Town, September, 1995, Rome.


Mauna Loa is a giant, active basaltic shield volcano which rises over 4  km above sea level, another 5  km above the north-central Pacific seafloor, and another 8  km above the isostatically depressed seafloor of the Pacific Plate, for a total volcanic height of 17  km. It is the most voluminous volcano on Earth (>75,000  km³ ), with a subareal surface area of over 5,000  km² (half the Island of Hawaii). Mauna Loa is one of the Earth's most active volcanoes, having erupted more than 30 times since its first documented historical eruption in 1843. Mauna Loa has been selected as one of 15 "Decade Volcanoes" by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI). This status provides opportunities for increased multidisciplinary and multinational efforts to understand volcanic processes and better monitor this great volcano, with the purpose of mitigating volcanic hazards at this and at similar volcanoes around the world.

Problems and Opportunities at Mauna Loa

The principal hazards posed by Mauna Loa eruptions are its frequent, high-volume lava flows (a Holocene coverage rate of about 40% per thousand years), the long lengths of these flows (5 have reached the sea since 1868), and lava fluidity (which results in high flow velocities -- especially on steep slopes). These flows pose serious risks to people living on lower slopes and to their properties. The recent recognition of the extent of major prehistoric submarine and subareal landslides from the south and west flanks of Mauna Loa is another long-term hazard here and at many other oceanic volcanoes. While the population at risk from Mauna Loa eruptions is small (about 75,000), the growth of Hawaii's tourist industry has produced large developments along the coast (more than $2 billion has been invested in new construction since the last eruption in 1984). The indiference of modern populations and governmental agencies to volcanic hazards also greatly increases risk. Whereas the Polynesian discoverers of Hawaii developed a respect for the destructive potential of Mauna Loa and learned to coexist with volcanic activity over millenia, recent immigrants tend to deny the potential for disaster, and regard eruptive activity as potentially "entertaining."

The principal importance of Mauna Loa to the Decade Volcano program derives not from the magnitude of the associated risk, however, but rather is related to its value as a "laboratory" for refinement of volcano monitoring and risk mitigation techniques. The excellent exposures and accessibility of the volcano make past and future lava flows ideal for detailed studies and observation. Mauna Loa has the best documented prehistoric eruptive chronology of any volcano on Earth, so that models of volcano genesis can be tested against the actual record of eruptive activity. The accumulated record of instrumental monitoring carried on by the Hawaiian Volcano Observatory over the past half century is a valuable resource, and its present instrumental network makes it one of the best monitored of all Decade Volcanoes (along with Etna and Sakurajima). Although much has been learned about Mauna Loa's seismicity and on-going deformation, the questions before us are much more numerous than the answers behind us. The deployment and testing of new monitoring equipment and techniques here can build on our past and present knowledge to better develop new methodologies for use at other Decade Volcanoes.

Progress Toward Decade Volcano Goals

A well-attended symposium at the Fall, 1993 meeting of the American Geophysical Union involved the presentation of nearly 40 papers about Mauna Loa (AGU, 1993). An informal meeting after the symposium led to the identification of about 50 scientists with an interest in Mauna Loa research. Since that meeting, most effort has focused on the production of a monograph about Mauna Loa, to be published by the AGU this Fall. The monograph, entitled Mauna Loa - a Decade Volcano will include about 20 papers, covering a wide spectrum of present-day Mauna Loa knowledge, in the fields of petrology, geochemistry, submarine geology, seismicity, deformation, gravity, remote sensing, historical and prehistoric chronology, long-term volcano evolution, ecology, and hazards analysis.

Future Plans

The principal need for future progress of the Muana Loa Decade Volcano Project is to establish better communications between (a) those directly involved in present or proposed Mauna Loa research, and (b) between Mauna Loa researchers and researchs at other Decade Volcanoes, so that the knowledge gained at Mauna Loa can be readily shared with others around the world, and so that we can learn of complementary efforts. Toward this end, those directly involved in Mauna Loa research need to better organize themselves, and modern electronic communication channels need to be developed. A Worldwide Web home page will be established this summer at the University of Hawaii for posting information about Mauna Loa Decade Volcano studies. The Internet address:
The webmaster for tis page is Prof. Gerard Fryer (address: -- contributions to this page are welcome!

As to specific avenues for future research, the following are considered important:

Volcanic processes

What additional studies of past eruptions could lead to a better understanding of eruptive style? What new technology should be employed to better understand the next Muana Loa eruption? Can specific individuals and equipment be identified (and funded) to be placed on "ready alert" to travel to Hawaii as soon as the next eruption appears imminent?

Geochemical and petrological processes

Much work has been done to characterize the compositional variability of Mauna Loa eruptive products. Are new or untried techniques appropriate to resolve unsolved (or unasked) questions about the genesis, storage, transport and eruption of Muana Loa magma or on the scale and dynamics of the Hawaiian plume?

Geophysical processes

What tools are needed to better assess the present internal structure of Mauna Loa and the dynamics of deformation, seismicity, thermal and electrical changes as magma intrudes and migrates within the Mauna Loa edifice? Could techniques be developed or applied to Mauna Loa to assess the susceptibility to giant landslides?

Remote sensing

Mauna Loa is one of the best-exposed and most accessible volcanoes on Earth for remote-sensing from airborne and orbiting platforms. New satellite systems with powerful tools for volcano analysis will be launched during the coming decade. What new information can be obtained about Mauna Loa from above, and how can this information best be integrated with expanded efforts at "ground-truth"? The remote-sensed data to be collected from Mauna Loa not only holds great promise for our understanding of this volcano, but will form the interpretational basis for studies of numerous volcanoes elsewhere on Earth and far beyond.

Biological significance

Mauna Loa has become the focus of major biological investigations, which involve understanding of rates and processes of forest growth, especially in the high-rainfall forests of the volcano's lower flanks. The ages and morphologies of underlying lava substrates are critical factors in the development of tropical rainforsets on young volcanoes, and the rates of volcano activity thus have major impact on forest dynamics. Studies of forest development rates can also provide information on the age of the underlying lava flows, and may thus allow low-cost, low-precision "dating" of lava flows at other volcanoes where laboratory dating of flows is not an option.

Atmospheric research

The Mauna Loa Observatory (MLO), an atnmospheric research facility of the National Atmospheric and Oceanic Administration, is located on Mauna Loa's north flank. Careful records of atmospheric composition for over 35 years have revealed a great deal about changing global atmospheric compositions, but have also obtained unique data about the local injection of CO2 and SO2 from Mauna Loa sources. Cooperative studeis between volcanic gas chemists and researchers at MLO during the Decade to come could yield new findings for both groups.

Lava dispersion

Development of appropriate contingency plans for engineering countermeasures to mitigate the impact of advancing lava flows.

Monitoring and public information

Incerased monitoring capability and beter understanding of the processes which lead to eruptions will enable scientists to give earlier warnings of imminent eruptive activity to threatened populations and to better advise local government agencies about land-use planning issues.

Decade Volcano Demonstration Projects are important components of the International Decade of Natural Disaster Reduction (Barberi and oithers, 1990). An essential Program is the need to develop and disseminate accumulating knowldege and new monitoring techniques which can be exported to other areas where populations are threatened by hazardous volcanoes. This ultimately is the most important purpose of Decade research ar Mauna Loa.


American Geophsyical Unon (1993), Fall Meeting Abstracts, EOS, Trans. Am. Geophys. Union, 74, n. 43, 742 pp.

Barberi, F.R., et al., Reducing volcanic disasters in the 1990's (1990), Volcanological Soc. Japan Bull., 35, 80.