10-01-2014, 05:28 AM
When talking about the Lava Zone Map one should probably study it. A copy of the original publication is here:
http://pubs.usgs.gov/mf/1992/2193/mf2193.pdf
In which it is noted that:
This map shows lava~flow hazard zones for the five volcanoes on the Island of Hawaii. Volcano boundaries are shown as heavy, dark bands, reflecting the overlapping of lava flows from adjacent volcanoes along their common boundary. Hazard-zone boundaries are drawn as double lines because of the geologic uncertainty in their placement. Most boundaries are gradational, and the change In the degree of hazard can be found over a distance of a mile or more. The general principles used to place hazard-zone boundaries are discussed by Mullineaux and others (1987) and Heliker (1990)....
And the zones themselves are:
Zone 1 - Includes summits and rift zones of Kilauea and Mauna Loa volcanoes, where vents have been repeatedly active in historical time.
Zone 2 - Areas adjacent to and downslope of zone 1. 15-25% of zone 2 has been covered by lava since 1800, and 25-75% has been covered within the past 750 years. Relative hazard within zone 2 decreases gradually as one moves away from zone 1.
Zone 3 - Areas less hazardous than zone 2 because of greater distance from recently active vents and (or) because of topography. 1-5% of zone 3 has been covered since 1800, and 15-75% has been covered within the past 750 years.
Zone 4 - Includes all of Hualalai, where the frequency of eruptions is lower than that for Kilauea or Mauna Loa. Lava coverage is proportionally smaller, about 5% since 1800, and less than 15% within the past 750 years.
Zone 5 - Area on Kilauea currently protected by topography
Zone 6 - Two areas on Mauna Loa, both protected by topography
Zone 7 - Younger part of Mauna Kea volcano. 20% of this area was covered by lava in the past 10,000 years.
Zone 8 - Remaining part of Mauna Kea. Only a few percent of this area has been covered by lava in the past 10,000 years.
Zone 9 - Kohala Volcano, which last erupted over 60,000 years ago.
They sound linear.. i.e. 1 through 9.. but they are a bit convoluted. It's best to study the map itself and read the description provided with it.
http://pubs.usgs.gov/mf/1992/2193/mf2193.pdf
In which it is noted that:
This map shows lava~flow hazard zones for the five volcanoes on the Island of Hawaii. Volcano boundaries are shown as heavy, dark bands, reflecting the overlapping of lava flows from adjacent volcanoes along their common boundary. Hazard-zone boundaries are drawn as double lines because of the geologic uncertainty in their placement. Most boundaries are gradational, and the change In the degree of hazard can be found over a distance of a mile or more. The general principles used to place hazard-zone boundaries are discussed by Mullineaux and others (1987) and Heliker (1990)....
And the zones themselves are:
Zone 1 - Includes summits and rift zones of Kilauea and Mauna Loa volcanoes, where vents have been repeatedly active in historical time.
Zone 2 - Areas adjacent to and downslope of zone 1. 15-25% of zone 2 has been covered by lava since 1800, and 25-75% has been covered within the past 750 years. Relative hazard within zone 2 decreases gradually as one moves away from zone 1.
Zone 3 - Areas less hazardous than zone 2 because of greater distance from recently active vents and (or) because of topography. 1-5% of zone 3 has been covered since 1800, and 15-75% has been covered within the past 750 years.
Zone 4 - Includes all of Hualalai, where the frequency of eruptions is lower than that for Kilauea or Mauna Loa. Lava coverage is proportionally smaller, about 5% since 1800, and less than 15% within the past 750 years.
Zone 5 - Area on Kilauea currently protected by topography
Zone 6 - Two areas on Mauna Loa, both protected by topography
Zone 7 - Younger part of Mauna Kea volcano. 20% of this area was covered by lava in the past 10,000 years.
Zone 8 - Remaining part of Mauna Kea. Only a few percent of this area has been covered by lava in the past 10,000 years.
Zone 9 - Kohala Volcano, which last erupted over 60,000 years ago.
They sound linear.. i.e. 1 through 9.. but they are a bit convoluted. It's best to study the map itself and read the description provided with it.