Mauna Loa 

By Julie Wallan

 

 

National Volcano Early Warning System

The developers of the emerging National Volcano Early Warning System began with simple and logical idea.  They realized that there often existed a gap between the threats volcanoes posed and their equivalent level of monitoring.  For example, they saw time and time again that an extremely dangerous volcano could present an even greater threat to a region because its current relative quiet state would limit it to hardly any of the necessary levels of monitoring.  The U.S. Geological Survey Volcano Hazards Program has joined forces with the rest of its partners in the Consortium of U.S. Volcano Observatories in order to assess the  current threats of  volcanoes in the United States, with the ultimate goal of nationally eliminating the discrepancy between their potential danger and current monitoring.  For more information visit http://pubs.usgs.gov/fs/2006/3142/. 

Source 21

 

Mauna Loa

Below is an assessment of the level of danger and of monitoring at Mauna Loa volcano, according to the processes and guidelines of the National Volcano Early Warning System.

 

 

Source 20 

Hazard and exposure factors used in threat assessment of U.S. volcanoes for the National Volcano Early Warning System.

See appendix text for discussion and explanation of abbreviations.

 

Hazards Factors

 

Score

Volcano type

If volcano type is cinder cone, basaltic field, small shield, or fissure vents: Score = 0

If volcano type is stratocone, lava domes, complex volcano, maar or caldera: Score = 1

 0

Maximum Volcano Explosivity Index (VEI)

If maximum known VEI ≤ 2: Score = 0

If maximum known VEI = 3 or 4: Score = 1

If maximum known VEI = 5 or 6: Score = 2

If maximum known VEI ≥ 7: Score = 3

If no maximum VEI is listed by GVP and if volcano type = 0: Score = 0

If no maximum VEI is listed by GVP but volcano type = 1: Score = 1

If no known Holocene eruptions and the volcano is not a silicic caldera system: Score = 0

 0

Explosive activity

If explosive activity (VEI ≥ 3) within the last 500 years: Score = 1

 0

Major explosive activity

If major explosive activity (VEI ≥ 4) within last 5000 years: Score = 1

 0

Eruption recurrence

If eruption interval is 1-99 years: Score = 4

If eruption interval is 100 – 1,000 years: Score = 3

If eruption interval is 1,000 to several thousand years: Score =2

If eruption interval is 5,000-10,000 years, or if no Holocene eruptions but it is a large-volume restless silicic system that has erupted in the last 100,000 years: Score = 1

If no known Holocene eruption: Score = 0

 4

 (See Eruptive History)

Holocene pyroclastic flows?

If yes: Score = 1

 0

Holocene lava flows?

If Holocene lava flows have traveled beyond the immediate eruption site or flanks and reached populated areas: Score =1

 1

(Source 1)

Holocene lahars?

If Holocene lahars have traveled beyond the flanks and reached populated areas: Score =1

 0

Holocene tsunami(s)?

Has it produced a tsunami within the Holocene? If yes: Score = 1

 0

Hydrothermal explosion potential?

If the volcano has had Holocene phreatic explosive activity, and/or the volcano has thermal features that are extensive enough to pose a potential for explosive activity: Score =1

 0

Sector collapse potential?

If the volcano has produced a sector collapse in Quaternary-Holocene time and has re-built its edifice, or, has high relief, steep flanks and demonstrated or inferred alteration: Score = 1

 0

Primary lahar source?

If volcano has a source of permanent water/ice on edifice, water volume > 106 m3: Score = 1

 0

 

 

 

 

Historical Unrest Factors

Score

Observed seismic unrest

Since the last eruption, in the absence of eruptive activity, within 20 km of the volcanic edifice? If yes: Score = 1

 1

 

(Source 23)

 

Observed ground deformation

Since the last eruption, in the absence of eruptive activity, inflation or other evidence of magma injection? If yes: Score = 1

 1

 

(Source 23)

 

Observed fumarolic or magmatic degassing

Since the last eruption, in the absence of eruptive activity, either heat source or magmatic gases? If yes: Score = 1

 1

 

(Source 15)

 

Total of Hazard Factors

 3

Exposure Factors

 

Log10 of Volcano Population Index (VPI) at 30 km

Calculated with LandScan population database. Visitor statistics for volcanoes in National Parks and other destination recreation areas are added to the VPI factor where available.

 4.74

Log10 of approximate population downstream or downslope

Population outside the 30 km VPI circle included within the extent of Holocene flow deposits or reasonable inundation modeling. This factor to be used only with volcanoes that have a primary lahar hazard (e.g. Cascade stratovolcanoes) or significant lava flow hazard (e.g. Mauna Loa).

 4.6

Historical fatalities?

If yes, and a permanent population is still present: Score = 1

 0

Historical evacuations?

If yes, and a permanent population is still present: Score = 1

 1

Local aviation exposure

If any type volcano is within 50 km of a jet-service airport, score = 1; if a Type 1 volcano is within 300 km of a jet-service airport, score = 1; if a Type 1 volcano is within 300 km of a major international airport, score = 2; if none of these criteria are met, score = 0.

 1

Regional aviation exposure

This score is based on the log10 of approximate daily passenger traffic in each region. At present, in the U.S., this score ranges from 4 to 5.15. The regional risk code is applied only to type 1 volcanoes and those type 0 volcanoes that have produced explosive eruptions.

 0

Power infrastructure

Is there power infrastructure (e.g., power generation/transmission/distribution for electricity, oil, or gas) within flowage hazard zones, or in an area frequently downwind of the volcano and close enough to considered at some risk? If yes, score =1

 0

Transportation infrastructure

Is there transportation infrastructure (e.g., port facilities, rail lines, major roads) within flowage hazard zones, or in an area frequently downwind of the volcano and close enough to considered at some risk? If yes, score = 1

 1

Major development or sensitive areas

Are there major developments or sensitive areas threatened (e.g., National Park facilities, flood control projects, government facilities, developed tourist/recreation facilities, manufacturing or other significant economic activity)? If yes, score =1

 1

Volcano is a significant part of a populated island

Holocene volcanic deposits cover >25% of land mass. If yes, score = 1

 1

Total of Exposure Factors

 14.34
Sum of all hazard factors x Sum of all exposure factors = Relative Threat Ranking
 43

 

Appendix 4: Guidelines for Rating the Level of Monitoring

LEVEL 4: WELL MONITORED IN REAL TIME

Monitoring should provide the ability to track detailed changes in real-time and to develop, test, and apply models of ongoing and expected activity.

• Seismic: 12-20 stations within 20 km of vent, including several near-field sites. Network includes numerous three-component stations and mix of other instrument types, including digital broadband stations, acoustic sensors, and accelerometers. Borehole instruments where practicable.

• Deformation: Routine surveys along with sufficient continuous stations (GPS, tiltmeters, and/or borehole dilatometers) to track closely geodetic changes in space and time and do detailed source modeling.

• Gas: Frequent airborne or campaign gas measurements. Arrays of continuous sensors and other types of gas measurements as appropriate for the volcano.

• Hydrologic: Level-3 coverage along with real-time monitoring of hill-slope soil moisture, stream discharge, etc., as appropriate. AFM systems for lahar detection where warranted.

• Remote sensing: Level 3 coverage along with other data from pertinent satellite sensors (e.g., daily multi-channel, high-resolution thermal-infrared images and frequent, high resolution, multi-channel visible images). Where practicable, continuous ground-based thermal imaging and Doppler radar coverage.

LEVEL 3: BASIC REAL-TIME MONITORING

Monitoring should provide the ability detect and track pre-eruptive and eruptive changes in real-time, with a basic understanding of what is occurring.

• Seismic: Network with 3-4 near-field stations and a total of at least six within 20 km of vent.

• Deformation: Routinely repeated surveys. At least six continuous stations (GPS and/or tiltmeters) in vicinity of volcano. LIDAR-derived images available for active features.

• Gas: Frequent airborne or campaign measurements of gas emissions (annually to monthly, as appropriate) along with support of 1-2 telemetered continuous sensors.

• Hydrologic: Level-2 coverage along with continuous-sensing probes in features of primary interest, including water wells. LIDAR-derived DEMs for lahar-runout modeling. cont’d.

• Remote sensing: Level 2 coverage along with routine use of multi-channel thermal-infrared data from ASTER-class satellite. Thermal and/or SAR overflights, as indicated by other monitoring data. Where practicable, remote video camera in operation.

LEVEL 2: LIMITED MONITORING FOR CHANGE DETECTION

Monitoring should provide the ability to detect and track activity frequently enough in near-real time to recognize that anomalous activity is occurring.

• Seismic: Regional network with 1-2 near-field stations in place (within ~10 km of volcano).

• Geodetic: Two or more surveys for establishing baseline. InSAR observations possible on summer-to-summer basis. At least three continuous stations (GPS or tiltmeters) in vicinity of volcano.

• Gas: Baseline of carbon-dioxide emission rate (or other gas as appropriate to the volcano).

• Hydrologic: Comprehensive database on temperatures and chemistry of springs and fumaroles.

Remote-Sensing: Regular processing and review of near-real-time meteorological satellite images (AVHRR, GOES), and/or review of non-real-time research satellite images (e.g., MODIS) by an observatory. Baseline inventory of air photos and/or satellite images with high spatial resolution (1 m).

LEVEL 1: MINIMAL MONITORING

Monitoring should provide the ability to detect that an eruption is occurring or that gross changes are occurring/have occurred near a volcano.

• Seismic –Volcano lies within a regional network; no near-field stations are in place but at least one station is within 50 km of the volcano. Or, a single near-field station is present, but no regional network exists.

• Remote sensing - Baseline inventory exists of Landsat-class satellite images. Routine scans for eruption clouds are conducted by meteorological agencies.

LEVEL 0: NO GROUND-BASED MONITORING

To score the current monitoring for a volcano the main monitoring methods (seismic, deformation, gas, hydrologic, and remote-sensing) are scored from 0-4. The average of the those scores is taken to give an overall monitoring score.
 


Mauna Loa Extent of Monitoring Score: 4

Overall Hazard and Monitoring Gap: 0

Mauna Loa is an extensively monitored volcano.  The Hawaiian Volcano Observatory produces daily, weekly, and monthly reports on the seismic activity, gas emissions, and other alterations taking place around the Mauna Loa caldera.  The Observatory has been able to gather a substantial eruptive history and establish an elaborate monitoring system because of the frequency of events, their substantial financial backing, and their experience as one of the oldest volcano monitoring stations in the world.  For more information, see Monitoring and Current Activity.