TY - JOUR
T1 - Recurrence Rates of Basaltic Volcanism in SP Cluster, San Francisco Volcanic Field, Arizona
AU - Conway, F. M.
AU - Connor, Charles B.
AU - Hill, B. E.
AU - Condit, C. D.
AU - Mullaney, K.
AU - Hall, C. M.
PY - 1998/7/1
Y1 - 1998/7/1
N2 - A new compilation of 23 K-Ar and 40 Ar- 39 Ar radiometric ages, stratigraphic and paleomagnetic correlations, and cone morphology from the SP cluster, San Francisco volcanic field, Arizona, is used to illustrate a quantitative approach to long-term volcanic hazards assessment for basaltic volcanic fields. SP cluster is a group of 67 basaltic cinder cones, tuff rings, spatter cones, and lava flows, all predominantly younger than 1700 ka. Relatively steady-state volcanic activity (1 volcano per 15 k.y.) has characterized the SP cluster since 780 ka. This activity has been concentrated in an ∼250 km 2 area since about 300 ka. We estimate that the chance of an eruption in the SP cluster during the next 1000 yr has an upper bound (95% confidence level) of 13%. Spatial and temporal probability models further indicate with 90% confidence that an eruption will take place within this 250 km 2 area of the SP cluster within the next 22–26 k.y., a rate of activity significantly greater than predicted by field-wide averages. Thus, spatial variations in recurrence rate of basaltic volcanism, such as those recognized in the SP cluster, should be considered in the formulation of hazard assessments.
AB - A new compilation of 23 K-Ar and 40 Ar- 39 Ar radiometric ages, stratigraphic and paleomagnetic correlations, and cone morphology from the SP cluster, San Francisco volcanic field, Arizona, is used to illustrate a quantitative approach to long-term volcanic hazards assessment for basaltic volcanic fields. SP cluster is a group of 67 basaltic cinder cones, tuff rings, spatter cones, and lava flows, all predominantly younger than 1700 ka. Relatively steady-state volcanic activity (1 volcano per 15 k.y.) has characterized the SP cluster since 780 ka. This activity has been concentrated in an ∼250 km 2 area since about 300 ka. We estimate that the chance of an eruption in the SP cluster during the next 1000 yr has an upper bound (95% confidence level) of 13%. Spatial and temporal probability models further indicate with 90% confidence that an eruption will take place within this 250 km 2 area of the SP cluster within the next 22–26 k.y., a rate of activity significantly greater than predicted by field-wide averages. Thus, spatial variations in recurrence rate of basaltic volcanism, such as those recognized in the SP cluster, should be considered in the formulation of hazard assessments.
UR - https://digitalcommons.usf.edu/geo_facpub/1669
UR - https://doi.org/10.1130/0091-7613(1998)026<0655:RROBVI>2.3.CO;2
U2 - /10.1130/0091-7613(1998)026<0655:RROBVI>2.3.CO;2
DO - /10.1130/0091-7613(1998)026<0655:RROBVI>2.3.CO;2
M3 - Article
VL - 26
JO - Geology
JF - Geology
ER -