Rapid emergency assessment of ash and gas hazard for future eruptions at Santorini Volcano, Greece

Table 3 Volcanological inputs for a ‘most likely’ long-duration ash emission with assumed event mass and duration (and thus mass flux) given two scenario cases: ‘Strong’ assumes that the Sparks et al. (1997) empirical relationship between plume height and mass flux is valid (i.e. the plume is not strongly affected by wind), while ‘Weak’ considers that the plume is affected by wind and follows the relationship of Woodhouse et al. (2013)

Height (km)	Number of events	Poisson rate parameter	Event ash mass (x10⁶ kg)		Duration (mins)		Particle size (phi)
Height (km)	Number of events	Poisson rate parameter	Strong	Weak	Strong	Weak	Particle size (phi)
Total eruption duration: 2 years
3	5	0.007	6	60	10	10	Range: −3.32 to 6.64
2	20	2.74 × 10⁻²	1.8	30	15	15	Median: 1.66
1	75	0.103	1.1	5.4	120	60	Standard deviation: 2
0.5	400	0.548	0.2	1.1	360	180	Standard deviation: 2
Scenario variants to investigate the effect of ash aggregation
Particle size is modified to favour larger particles.							Range: −3.32 to 3.32
All parameters as for the base Santorini ‘Weak’ and ‘Strong’ scenarios.							Median: 0.00
							Standard deviation: 2
Scenario variants to investigate the effect of event clustering
Total eruption duration: 1 year
3	5	0.014	Increased Poisson rate parameter simulates shorter inter-event times.
2	20	5.48 x 10⁻²
1	75	0.205	All other parameters as for the base Santorini ‘Weak’ and ‘Strong’ scenarios.
0.5	400	1.096

Duration refers to individual events, rather than the total eruption duration, and relates to the event ash mass and calculated mass flux. Further variants build upon these base scenarios to investigate the influence of aggregation and event clustering on simulated hazard

ISSN: 2191-5040