Mauna Loa

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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 19.475°N
  • 155.608°W

  • 4170 m
    13678 ft

  • 332020
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

24 March-30 March 2010

On 30 March, HVO reported that the Aviation Color Code and the Volcano Alert Level for Mauna Loa were both lowered to Green and Normal, respectively. Deformation had not been noted since mid-2009 and seismicity was at normal levels.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)



 Available Weekly Reports


2010: March
2005: August
2004: September | October
2003: January | March | May
2002: May | September | October


24 March-30 March 2010

On 30 March, HVO reported that the Aviation Color Code and the Volcano Alert Level for Mauna Loa were both lowered to Green and Normal, respectively. Deformation had not been noted since mid-2009 and seismicity was at normal levels.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


17 August-23 August 2005

HVO reported on 21 August that extension across Mauna Loa's summit had resumed over the previous few weeks after pausing for much of July. Seismicity remained at low levels at the volcano.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


13 October-19 October 2004

According to HVO, since early July 2004 an increased number of earthquakes had been recorded from beneath Mauna Loa. From week to week, the numbers fluctuated but remained well above the norm. During the week ending 13 October, 110 earthquakes were located under the summit, up from 47 for the week ending 6 October. Through 13 October, more than 730 earthquakes related to the ongoing seismic activity have been centered beneath Mauna Loa's summit caldera and the adjacent part of the southwest rift zone.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


6 October-12 October 2004

According to HVO, since early July 2004 an increased number of earthquakes had been recorded from beneath Mauna Loa. From week to week, the numbers fluctuated but remained well above the norm. Through September, more than 580 earthquakes were centered beneath Mauna Loa's summit caldera and the adjacent part of the southwest rift zone. Most of these earthquakes were quite deep, from 35 to 50 km below the ground surface and small, less than M 3. They were "long-period" (LP) earthquakes, which means that their signals gradually rise out of the background rather than appearing abruptly. Such a concentrated number of deep LP earthquakes from this part of Mauna Loa is unprecedented, at least in the modern earthquake record dating back to the 1960s. During about 4-11 October, however, only 23 earthquakes were located under the summit.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


22 September-28 September 2004

No changes were noted by HVO at Mauna Loa through 27 September. Since early July 2004, an increasing number of earthquakes had been recorded from beneath Mauna Loa. From week to week the numbers fluctuated but remained well above the earlier established norm. Through the third week of September, more than 560 earthquakes were centered beneath Mauna Loa's summit caldera and the adjacent part of the southwest rift zone. Most of these earthquakes were quite deep, 35-50 km below the surface, and less than M 3. Inflation continued at the summit and showed no change during the increased seismic activity.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


15 September-21 September 2004

No changes have been noted by HVO at Mauna Loa through 21 September. Since early July 2004, an increasing number of earthquakes has been recorded from beneath Mauna Loa. From week to week the numbers fluctuate but remain well above the earlier established norm. Through the second week of September, more than 500 earthquakes were centered beneath the summit caldera and the adjacent part of the southwest rift zone. Most of these earthquakes were quite deep, 35-50 km below the surface, and less than M 3. Inflation was continuing at the summit and has so far shown no change during the increased seismic activity.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


8 September-14 September 2004

HVO reported that beginning in early July 2004 an increasing number of earthquakes had been recorded beneath Mauna Loa. From week to week, the numbers fluctuated but remained well above the norm. Through the first week of September, more than 350 earthquakes were centered beneath Mauna Loa's summit caldera and the adjacent part of the southwest rift zone. Most of these earthquakes were quite deep, from 35 to 50 km below the ground surface. They were "long-period" (LP) earthquakes, which means that their signals gradually rise out of the ambient seismic background. Such a concentrated number of deep LP earthquakes from this part of Mauna Loa is unprecedented, at least in the modern earthquake catalog dating back to the 1960s. Inflation continued at the summit and as of 12 September showed no change during the increased seismic activity.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


14 May-20 May 2003

HVO reported on 18 May that inflation may have resumed at Mauna Loa's summit during the week, after slackening off following an increase in mid-February. Seismicity, however, remained low. Inflation was noted where the GPS network first showed definite lengthening of the lines across the summit caldera in late April or May 2002, after nearly 10 years of slight deflation. HVO interpreted the lengthening, uplift, and tilting to indicate resumed swelling of the magma reservoir within the volcano.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


12 March-18 March 2003

HVO reported on 16 March 2003 that renewed inflation at Mauna Loa's Moku`aweoweo summit caldera began in late February 2003. The GPS network first showed inflation in late April or May 2002, which tailed off and perhaps stopped in mid-winter. The lengthening, uplift, and tilting were interpreted to indicate resumed swelling of the magma reservoir within Mauna Loa. Seismicity remained at low levels.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


22 January-28 January 2003

HVO reported on 27 January that during the previous couple of months the rate of lengthening across Mauna Loa's summit caldera (Moku`aweoweo) slowed significantly. The lengthening started in late April or May, as did uplift measured by GPS and ground tilt measured by several dry-tilt stations. As of the 27th, seismicity remained at low levels.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


30 October-5 November 2002

On the afternoon of 1 November volcanic tremor, centered low on Mauna Loa's SE flank, occurred for 30 minutes. HVO stated that this is a common occurrence, taking place several times a year in the same general region. The permanent, continuous GPS network indicated ongoing lengthening across Moku`aweoweo summit caldera, as it has since late April or May 2002.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


23 October-29 October 2002

As of 28 October Mauna Loa continued to inflate, but seismicity remained at low levels. The permanent, continuous GPS network indicated ongoing lengthening across Moku`aweoweo summit caldera, as it has since late April or May 2002.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


9 October-15 October 2002

A brief period of low-amplitude tremor occurred at Mauna Loa's summit on 7 October, lasting several minutes. It apparently was triggered by, or at least quickly followed, a small earthquake. The following day, several more small earthquakes took place. By the 10th, seismicity had returned to low levels. During 8-15 October, the permanent continuous global positioning system network indicated that ongoing lengthening occurred across Moku`aweoweo summit caldera as it has since late April or May.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


25 September-1 October 2002

HVO reported on 30 September that a pattern of slow deflation occurring at Mauna Loa for the past 9 years abruptly changed in mid-May when the summit area began to slowly swell and stretch. Global Positioning System measurements revealed that distances across the summit caldera (Moku`aweoweo) have been lengthening at a rate of 5-6 cm per year, and the caldera has widened about 2 cm since 12 May. The summit area was slightly higher than before mid-May, consistent with swelling. In addition, the upper part of the SE flank showed outward movement. Seismicity remained low at Mauna Loa, although it may have been slightly higher level than during the pre-inflation interval.

Sources: US Geological Survey Hawaiian Volcano Observatory (HVO), US Geological Survey Hawaiian Volcano Observatory (HVO), Associated Press


1 May-7 May 2002

A small earthquake cluster event, with magnitudes between 1.1-1.7, occurred at Mauna Loa during 19-26 April. There were no signs indicating that an eruptive event was imminent and no significant deformation was recorded.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)


Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1984 Mar 25 1984 Apr 15 Confirmed 0 Historical Observations Mokuaweoweo, SW and NE rift zones
1975 Jul 5 1975 Jul 6 Confirmed 0 Historical Observations Mokuaweoweo and NE and SW rift zones,
1950 Jun 1 1950 Jun 23 Confirmed 0 Historical Observations SW rift zone (2440 m)
1949 Jan 6 1949 May 31 Confirmed 0 Historical Observations Mokuaweoweo and SW rift zone
1942 Apr 26 1942 May 10 Confirmed 0 Historical Observations NE rift zone (2800 m) and Mokuaweoweo
1940 Apr 7 1940 Aug 18 Confirmed 0 Historical Observations Mokuaweoweo and SW rift zone
1935 Nov 21 1936 Jan 2 Confirmed 0 Historical Observations NE rift zone (3690 m) and Mokuaweoweo
1933 Dec 2 1933 Dec 18 Confirmed 0 Historical Observations Mokuaweoweo
1926 Apr 10 1926 Apr 28 (?) Confirmed 0 Historical Observations SW rift (2320 m)
1919 Sep 26 1919 Nov 5 (?) Confirmed 0 Historical Observations SW rift zone (3450 and 2350 m)
1916 May 19 1916 May 30 Confirmed 0 Historical Observations SW rift zone (3000 and 2250 m)
1914 Nov 25 1915 Jan 11 Confirmed 0 Historical Observations Mokuaweoweo
1907 Jan 9 1907 Jan 24 (in or after) Confirmed 0 Historical Observations SW rift zone (1890 m) and Mokuaweoweo
1903 Sep 1 1903 Dec 7 (?) Confirmed 0 Historical Observations Mokuaweoweo
1899 Jul 1 1899 Jul 23 Confirmed 1 Historical Observations NE rift zone (3260 m) and Mokuaweoweo
1896 Apr 21 1896 May 6 Confirmed 0 Historical Observations Mokuaweoweo
1892 Nov 30 1892 Dec 3 Confirmed 0 Historical Observations Mokuaweoweo
1887 Jan 16 1887 Jan 28 (?) Confirmed 0 Historical Observations SW rift zone (1740 m) and Mokuaweoweo
1880 Nov 5 1881 Aug 10 Confirmed 1 Historical Observations NE rift zone (3170 m)
1880 May 1 1880 May 6 Confirmed 1 Historical Observations Mokuaweoweo
1879 Mar 9 1879 Mar 9 (?) Confirmed 0 Historical Observations Mokuaweoweo
1877 Feb 14 1877 Feb 24 Confirmed 0 Historical Observations Mokuaweoweo, submarine west flank
1876 Feb 13 1876 Feb 14 (?) Confirmed 0 Historical Observations Mokuaweoweo
1875 Aug 11 1875 Aug 18 (?) Confirmed 0 Historical Observations Mokuaweoweo
1875 Jan 10 1875 Feb 9 (?) Confirmed 0 Historical Observations Mokuaweoweo
1873 Apr 20 1874 Oct 19 (?) Confirmed 1 Historical Observations Mokuaweoweo
1873 Jan 6 1873 Jan 7 (?) Confirmed 0 Historical Observations Mokuaweoweo
1872 Aug 9 1872 Sep Confirmed 1 Historical Observations Mokuaweoweo
1871 Aug 10 1871 Aug 30 (?) Confirmed 0 Historical Observations Mokuaweoweo
[ 1870 Jan 1 (?) ] [ 1870 Jan 15 (?) ] Uncertain 0   Mokuaweoweo
1868 Mar 27 1868 Apr 22 Confirmed 2 Historical Observations SW rift zone (1000 m) and Mokuaweoweo
1865 Dec 30 1866 Apr 29 (?) Confirmed 0 Historical Observations Mokuaweoweo
1859 Jan 23 1859 Nov 25 Confirmed 1 Historical Observations North flank (2800 m) and Mokuaweoweo
1855 Aug 11 1856 Nov Confirmed 1 Historical Observations NE rift zone (3200 m) and Mokuaweoweo
1852 Feb 17 1852 Mar 11 (?) Confirmed 2 Historical Observations NE rift zone (2560 m) and Mokuaweoweo
1851 Aug 8 1851 Aug 11 ± 1 days Confirmed 0 Historical Observations Mokuaweoweo and SW rift zone
1849 May Unknown Confirmed 0 Historical Observations Mokuaweoweo
1843 Jan 9 1843 Apr 10 (?) Confirmed 0 Historical Observations North flank, Mokuaweoweo and NE rift
1832 Jun 20 1832 Jul 15 ± 7 days Confirmed 0 Historical Observations Mokuaweoweo and adjacent vents
1750 (?) Unknown Confirmed 0 Historical Observations North flank (2380 m) and SW rift zone?
1730 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1685 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1680 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NW flank
1650 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1640 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1540 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1510 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1500 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1470 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1440 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone and NW flank
1390 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1370 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone and Mokuaweoweo
1360 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1310 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
1190 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone and Mokuaweoweo
1170 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1130 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
1070 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1040 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
0940 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
0830 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo and NW flank
0810 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
0680 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
0630 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
0600 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
0550 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
0480 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
0450 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
0350 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
0300 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
0200 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
0150 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SE rift zone
0100 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SE rift zone
0050 (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
0030 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE and SW rift zones
0060 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
0080 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SE rift zone
0200 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
0300 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
0400 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
0500 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
0600 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
0950 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
1300 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo and NE rift zone
1650 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE and SW rift zones
1700 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
1750 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
1800 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NW and SW rift zones
1900 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
2000 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
2050 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
2150 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
2250 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
2350 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
2750 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE and SW rift zones
3250 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
3350 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
3750 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
4250 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
5350 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
5650 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
5850 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE and SW rift zones
6250 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
6550 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) Mokuaweoweo
6650 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
7150 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE and SW rift zones
7350 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) SW rift zone
7550 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
7850 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone
8050 BCE (?) Unknown Confirmed 0 Radiocarbon (uncorrected) NE rift zone

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Brigham W T, 1909. The volcanoes of Kilauea and Mauna Loa. Mem B P Bishop Museum, 2: 1-222.

Garcia M O, Davis M G, 2001. Submarine growth and internal structure of ocean island volcanoes based on submarine observations of Mauna Loa volcano, Hawaii. Geology, 29: 163-166.

Green J, Short N M, 1971. Volcanic Landforms and Surface Features: a Photographic Atlas and Glossary. New York: Springer-Verlag, 519 p.

Hitchcock C H, 1909. Hawaii and its Volcanoes. Honolulu: Hawaiian Gazette Pub Co, 306 p.

Jurado-Chichay Z, Rowland S K, 1995. Channel overflows of the Pohue Bay flow, Mauna Loa, Hawai'i: examples of the contrast between surface and interior lava. Bull Volc, 57: 117-126.

Jurado-Chichay Z, Rowland S K, Walker G P L, 1996. The formation of circular littoral cones from tube-fed pahoehoe, Mauna Loa, Hawai'i. Bull Volc, 57: 471-482.

Lipman P W, 1995. Declining growth of Mauna Loa during the last 10,000 years: rates of lava accumulation vs. gravitational subsidence. In: Rhodes J M, Lockwood J P (eds), {Mauna Loa Revealed. Structure, Composition, History, and Hazards}. Geophys Monogr, 92: 45-80.

Lockwood J P, Lipman P W, 1987. Holocene eruptive history of Mauna Loa volcano. U S Geol Surv Prof Pap, 1350: 509-535.

Macdonald G A, 1955. Hawaiian Islands. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 3: 1-37.

Moore J G, Clague D A, Holcomb R T, Lipman P W, Normark W R, Torresan M E, 1989. Prodigious submarine landslides on the Hawaiian Ridge. J Geophys Res, 94: 17,465-17,484.

Newhall C G, Dzurisin D, 1988. Historical unrest at large calderas of the world. U S Geol Surv Bull, 1855: 1108 p, 2 vol.

Riker J M, Cashman K V, Kauahikaua J P, Montierth C M, 2009. The length of channelized lava flows: Insight from the 1859 eruption of Mauna Loa volcano, Hawaii. J Volc Geotherm Res, 183: 139-156.

Robinson J E, Eakins B W, 2006. Calculated volumes of individual shield volcanoes at the young end of the Hawaiian Ridge. J Volc Geotherm Res, 151: 309-317.

Wanless V D, Garcia M O, Rhodes J M, Weis D, Norman M D, 2006. Shield-stage alkalic volcanism on Mauna Loa volcano, Hawaii. J Volc Geotherm Res, 151: 141-155.

Yokose H, Lipman P W, 2004. Emplacement mechanisms of the South Kona slide complex, Hawaii Island: sampling and observations by remotely operated vehicle Kaiko. Bull Volc, 66: 569-584.

Zimbelman J R, Garry W B, Johnston A K, Williams S H, 2008. Emplacement of the 1907 Mauna Loa basalt flow as derived from precision topography and satellite imaging. J Volc Geotherm Res, 177: 837-847.

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.