Statistical distribution of volcanism: example for Caribou
volcanic field, Lassen Volcanic region, California
- Dynamic Hazard Maps home page
- Volcanology group home page
1- Gather existing geologic data:
- vent locations: 114 cones and shields
- geological maps: Muffler et al., 2010, USGS
- geochemistry: basaltic andesites <63% SiO2
- volumes of lava flows and edifices = ~50 cubic km
- timing of eruptive events (stratigraphic relationships,
radiometric dating, and palaeomagnetism): ~ 450 - 18 ka
- geophysical data (gravity, magnetics, seismic refraction,
crustal velocity models, tomography...): Berge & Stauber,1987
2- Develop and test statistical models:
Spatial intensity of volcanism, recurrence rate, and volume flux are
used to recast discrete volcanic events (e.g. dike intrusion and
eruption) as continuous probability density functions.
- Spatial intensity maps identify volcano clustering, suggest tectonic controls on magma
ascent, and identify magmatic footprints (95 or 99 % of spatial intensity).
A Gaussian kernel function and unique 2-D, elliptical, smoothing
bandwidth to estimate the spatial intensity of volcanism based on
vent locations (the intensity has its maximum centered at the vent
location and decreases with distance from this point). Total spatial
intensity at a point is calculated by summing each vent's
contribution to the intensity estimation (left).
- Spatial intensity of erupted volume (volume/km²)
highlights zones of high vs. low magma productivity. Results can
clusters, geophysical data.
- Spatio-temporal changes of spatial density and magma
productivity allow to establish a spatial and temporal
model of source productivity and transport.
3- Compile a database of outputs:
- Catalog of vent locations, lava volumes, age plus uncertainty,
stratigraphic relationships, paleomagnetic polarity,
- Spatial intensity maps
- Spatial distribution of magma focusing: zones of high or low
- Spatio-temporal evolution of volcanism