TY - JOUR

T1 - Global database of large magnitude explosive eruptions for magnitude-frequency analysis

AU - Hobbs, Laura Kate

AU - Sparks, Steve

AU - Deligne, Natalia Irma

AU - Coles, Stuart

AU - Dunning, Hayley A.

PY - 2008

Y1 - 2008

N2 - Large explosive volcanic eruptions can have severe consequences for life, propertyand climate. In the most extreme cases this can cause catastrophes on a global scale.Extreme value statistics can be used to evaluate the magnitude-frequency relationshipof large magnitude explosive events, and also to assess how the quality of the volcanicrecord affects these results. Applying extreme value statistics to databases of explosivevolcanic eruptions with a Volcanic Explosivity Index (VEI) of 4 or greater inthe last 2000 and 10,000 years has yielded results that suggest the ability to constrainmagnitude-frequency relationships for very large events is limited due to underrecordingof the data which increases with age. Further analysis shows that this is dependenton both timing and the size of a given eruption; larger eruptions are more likely tobe found in the historical or geological records. Analysis of the 10,000 year datasetpredicted that a magnitude 8.0 eruption has a 40% chance of being recorded prior to 1AD, and a magnitude 6.0 eruption only a 20% chance. However, as the repose periodbetween events will increase with the size of the eruptions, the return periods of thelargest and most devastating explosive eruptions are likely to exceed 10,000 years.In order to build on previous results, the eruption database has been expanded to includedata extending back to greater than 1,000,000 years, with the aim of again usingextreme value statistics to determine global frequency of large magnitude explosiveeruptions. As predicted by earlier results, the record of volcanism decreases dramaticallyback through time, particularly beyond 100,000 years and the statistical modelcan be applied to take account of underrecording to quantify its effects. An updatedmagnitude-frequency relationship for large explosive eruptions is presented.

AB - Large explosive volcanic eruptions can have severe consequences for life, propertyand climate. In the most extreme cases this can cause catastrophes on a global scale.Extreme value statistics can be used to evaluate the magnitude-frequency relationshipof large magnitude explosive events, and also to assess how the quality of the volcanicrecord affects these results. Applying extreme value statistics to databases of explosivevolcanic eruptions with a Volcanic Explosivity Index (VEI) of 4 or greater inthe last 2000 and 10,000 years has yielded results that suggest the ability to constrainmagnitude-frequency relationships for very large events is limited due to underrecordingof the data which increases with age. Further analysis shows that this is dependenton both timing and the size of a given eruption; larger eruptions are more likely tobe found in the historical or geological records. Analysis of the 10,000 year datasetpredicted that a magnitude 8.0 eruption has a 40% chance of being recorded prior to 1AD, and a magnitude 6.0 eruption only a 20% chance. However, as the repose periodbetween events will increase with the size of the eruptions, the return periods of thelargest and most devastating explosive eruptions are likely to exceed 10,000 years.In order to build on previous results, the eruption database has been expanded to includedata extending back to greater than 1,000,000 years, with the aim of again usingextreme value statistics to determine global frequency of large magnitude explosiveeruptions. As predicted by earlier results, the record of volcanism decreases dramaticallyback through time, particularly beyond 100,000 years and the statistical modelcan be applied to take account of underrecording to quantify its effects. An updatedmagnitude-frequency relationship for large explosive eruptions is presented.

M3 - Meeting abstract

VL - 10

JO - Geophysical Research Abstracts

JF - Geophysical Research Abstracts

SN - 1029-7006

M1 - A00064

ER -