Mudpots, small geysers, and vigorous, noisy fumaroles
Part of the EVS report follows. "During our observations at 1100 on 9 July intense and noisy gas emissions (like a jet engine) occurred near the low NW part of the inner wall of the crater. These gas emissions generated a gray-white plume. This area of the crater was covered by many yellow sulfur deposits. A strong smell of hydrogen sulfide was also noted. An important solfatara zone surrounded the NW, N, NE, and E sides of the green, ~40,000 m3, acidic crater lake. Two small geysers, the one in the N and the other in the NW, were very active (2-3 m height). Several boiling basins and mud pots were active around the lake. It was not possible to get down into the crater without rock climbing equipment, because the crater walls were very steep." EVS observers also proposed that a low part of the S wall had collapsed.
Information Contacts: H. Gaudru, C. Pittet, M. Auber, C. Bopp, and O. Saudan, EVS, Switzerland.
The Global Volcanism Program has no Weekly Reports available for Mahawu.
Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.
Tectonic earthquakes, plume, elevated lake temperature
Beginning on 17 April, a white plume was observed ~100 m above Mahawu crater. The plume persisted into early May. Between 1 and 22 April, tectonic earthquakes occurred at a rate of 1/day, with no shallow volcanic earthquakes. During the last week of April, tectonic earthquakes occurred at a rate of ~9/day and shallow volcanic events at ~5/day.
Mahawu contains a crater lake with a volume of ~40,000 m3 of greenish-yellow water. On 21 April the temperature of the lake water was 45°C, compared to a normal 20°C measured in September 1986. A strong odor of H2S was also noted by the VSI observer during his 21 April visit. VSI recommended that a circular area extending ~3.5 km from the crater be temporarily closed to public access. In January 1978, the temperature of the lake water reached 70°C without an eruption [but see 12:7 & 8].
Information Contacts: T. Casadevall, USGS & VSI.
Lake volume and temperature increase, seismicity rises
A 100-m white plume was first seen emerging from the summit crater on 17 April (12:04). A similar whitish plume was continuously present above the summit in May and June. Both tectonic and volcanic earthquakes had increased at the end of April and continued to be recorded in May and June. By 30 June, the crater lake volume had increased to 45,000 m3 and water temperature had increased to 48°C.
Information Contacts: VSI.
White plume present, 1977 activity reviewed
White fume was continuously present above the crater rim to 100 m heights. Fewer than five volcanic earthquakes were recorded/day. Some tectonic earthquakes were also recorded.
In 12:4 we reported that the temperature of the crater lake rose to 70°C in January 1978 without an eruption. However, Nairn and Bachri (1978) report that on 16 November 1977, the crater lake, 800 m in diameter and 10 m deep, was gray colored and turbid with strong central upwelling and had a temperature of 85.5°C [but see 12:8]. Moderately loud explosions were heard every 5-10 minutes followed by 2-3-m-high spearhead projections of water and lake-floor debris. Along the NE shore fine gray mud was deposited to 20 m above the lake. A strong H2S odor was present.
Reference. Nairn, I. and Bachri, S., 1978, Several annotations about Mahawu's crater activities in recent times: Berita Direktorat Geologi, v. 10, no. 5, p. 55.
Information Contacts: VSI.
1977 lake data corrected
During the November 1977 visit by Nairn and Bachri, the crater lake was 80 m in diameter and its temperature was 65.5°C (correcting the values reported in 12:07). Lake depth was estimated at 10 m by a guide, based on his earlier observation of the crater floor at a time when the lake was dry. The explosions from the lake were quite small.
Information Contacts: I. Nairn, NZGS Rotorua, New Zealand.
Increased thermal activity
Mahawu began to show signs of renewed activity in mid-Nov, about a month after the eruption of Lokon-Empung, 7 km WNW. Temperatures increased at the solfataras and fumaroles in and around the crater lake, and a vapor column rose 50-200 m above the crater. Although no magmatic eruption was observed, mud boiling from the base of the crater lake generated tremor with 1-2 mm amplitude. No volcanic tremor was detected. As of mid-Dec, degassing episodes were decreasing in number and intensity.
Information Contacts: VSI.
Mudpots, small geysers, and vigorous, noisy fumaroles
Part of the EVS report follows. "During our observations at 1100 on 9 July intense and noisy gas emissions (like a jet engine) occurred near the low NW part of the inner wall of the crater. These gas emissions generated a gray-white plume. This area of the crater was covered by many yellow sulfur deposits. A strong smell of hydrogen sulfide was also noted. An important solfatara zone surrounded the NW, N, NE, and E sides of the green, ~40,000 m3, acidic crater lake. Two small geysers, the one in the N and the other in the NW, were very active (2-3 m height). Several boiling basins and mud pots were active around the lake. It was not possible to get down into the crater without rock climbing equipment, because the crater walls were very steep." EVS observers also proposed that a low part of the S wall had collapsed.
Information Contacts: H. Gaudru, C. Pittet, M. Auber, C. Bopp, and O. Saudan, EVS, Switzerland.
This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.
Synonyms |
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Mahawoe | Roemengan | Rumengan | ||||
Cones |
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Feature Name | Feature Type | Elevation | Latitude | Longitude |
Masarang | Cone | 1236 m | ||
Tombuluan | Cone | 455 m | ||
Craters |
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Feature Name | Feature Type | Elevation | Latitude | Longitude |
Niawuan | Crater | |||
Wagio | Crater |
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There is data available for 7 confirmed Holocene eruptive periods.
1977 Nov 16 Confirmed Eruption VEI: 0
Episode 1 | Eruption | ||||||||||||||||||||
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1977 Nov 16 - Unknown | Evidence from Observations: Reported | |||||||||||||||||||
List of 2 Events for Episode 1
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1958 Jul 12 - 1958 Jul 29 Confirmed Eruption VEI: 2 (?)
Episode 1 | Eruption | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
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1958 Jul 12 - 1958 Jul 29 | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
List of 9 Events for Episode 1
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1952 Jul 2 ± 182 days Confirmed Eruption VEI: 2 (?)
Episode 1 | Eruption | |||||||||||||||
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1952 Jul 2 ± 182 days - Unknown | Evidence from Observations: Reported | ||||||||||||||
List of 1 Events for Episode 1
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1904 Oct 4 (in or before) Confirmed Eruption VEI: 2
Episode 1 | Eruption | |||||||||||||||||||||||||
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1904 Oct 4 (in or before) - Unknown | Evidence from Observations: Reported | ||||||||||||||||||||||||
List of 3 Events for Episode 1
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1846 Confirmed Eruption VEI: 2
Episode 1 | Eruption | ||||||||||||||||||||
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1846 - Unknown | Evidence from Observations: Reported | |||||||||||||||||||
List of 2 Events for Episode 1
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1789 Dec 31 ± 365 days Confirmed Eruption VEI: 2
Episode 1 | Eruption | |||||||||||||||||||||||||
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1789 Dec 31 ± 365 days - Unknown | Evidence from Observations: Reported | ||||||||||||||||||||||||
List of 3 Events for Episode 1
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1788 (in or before) Confirmed Eruption
Episode 1 | Eruption | |||||||||||||||
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1788 (in or before) - Unknown | Evidence from Observations: Reported | ||||||||||||||
List of 1 Events for Episode 1
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There is no Deformation History data available for Mahawu.
There is no Emissions History data available for Mahawu.
Maps are not currently available due to technical issues.
The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included.
There are no samples for Mahawu in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.
Copernicus Browser | The Copernicus Browser replaced the Sentinel Hub Playground browser in 2023, to provide access to Earth observation archives from the Copernicus Data Space Ecosystem, the main distribution platform for data from the EU Copernicus missions. |
MIROVA | Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity. |
MODVOLC Thermal Alerts | Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales. |
WOVOdat
Single Volcano View Temporal Evolution of Unrest Side by Side Volcanoes |
WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
GVMID Data on Volcano Monitoring Infrastructure The Global Volcano Monitoring Infrastructure Database GVMID, is aimed at documenting and improving capabilities of volcano monitoring from the ground and space. GVMID should provide a snapshot and baseline view of the techniques and instrumentation that are in place at various volcanoes, which can be use by volcano observatories as reference to setup new monitoring system or improving networks at a specific volcano. These data will allow identification of what monitoring gaps exist, which can be then targeted by remote sensing infrastructure and future instrument deployments. |
Volcanic Hazard Maps | The IAVCEI Commission on Volcanic Hazards and Risk has a Volcanic Hazard Maps database designed to serve as a resource for hazard mappers (or other interested parties) to explore how common issues in hazard map development have been addressed at different volcanoes, in different countries, for different hazards, and for different intended audiences. In addition to the comprehensive, searchable Volcanic Hazard Maps Database, this website contains information about diversity of volcanic hazard maps, illustrated using examples from the database. This site is for educational purposes related to volcanic hazard maps. Hazard maps found on this website should not be used for emergency purposes. For the most recent, official hazard map for a particular volcano, please seek out the proper institutional authorities on the matter. |
IRIS seismic stations/networks | Incorporated Research Institutions for Seismology (IRIS) Data Services map showing the location of seismic stations from all available networks (permanent or temporary) within a radius of 0.18° (about 20 km at mid-latitudes) from the given location of Mahawu. Users can customize a variety of filters and options in the left panel. Note that if there are no stations are known the map will default to show the entire world with a "No data matched request" error notice. |
UNAVCO GPS/GNSS stations | Geodetic Data Services map from UNAVCO showing the location of GPS/GNSS stations from all available networks (permanent or temporary) within a radius of 20 km from the given location of Mahawu. Users can customize the data search based on station or network names, location, and time window. Requires Adobe Flash Player. |
DECADE Data | The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the Mapping Gas Emissions (MaGa) Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO2 to the atmosphere, but installing CO2 monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere. |
Large Eruptions of Mahawu | Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA). |
EarthChem | EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS). |