Page 84 - Caldera Volcanism Analysis, Modelling and Response

Pyroclastic Density Currents 59

Figure 1 Examples of generation of PDCs from di¡erent eruptive mechanisms. (a) Dome
collapse at Soufriere Hills volcano, Montserrat (photo from Montserrat Volcano Observatory
website); (b) PDCs generated by partial column collapses during the eruption of September
23,1984 eruption of Mayon volcano (photo from Newhall, USGS website); (c) PDC generation
by dome explosion at Soufriere Hills, Montserrat (photo from MontserratVolcano Observatory
website); (d) radial expanding PDC generated during phreatomagmatic activity at Capelinhos,
Azores (photo from San Diego State University website); (e) generation of PDC by a lateral
blast at the onset of May 18,1980 eruption of St Helens volcano (photo from USGS website);
(f ) sketch of PDC generation by continuous column collapse; (g) sketch of PDC generation
by boiling over mechanism.