Moi, Paul Derand

While investigating about how dangerous each volcano was what types of threat each of them poses, etc, I created a scale to classify them in terms of danger.

The scale is influenced by the Volcanic Activity Index (VAI) and the population that could be affected by at least two different hazards linked to an eruption.

dangerosity = (VAI) * (log (population in thousands of inhabitants))

If of the VAI and/or the logarithm of the population in kilo-inhabitants is/are negative, they should be changed to zero.

In this way it is impossible to have a volcano with a negative dangerosity. However, the top of the scale is open.

Here is a list of some volcanoes, classified by their dangerosity. We can see that half of them roughly have a dangerosity between 3,1 and 0,6, with a median of 1,7:

Class 6 to 6.9 (3 volcanoes):

Etna (6,9), Vesuvius (6,3), Merapi (6,2)

Class 5 to 5.9 (3 volcanoes):

Nyiragongo (5,9), Nevado del Ruiz (5,3), Popocatepetl (5,1)

Class 4 to 4.9 (5 volcanoes):

Santa Maria (4,9), Sakurajima (4,2), Grimsvotn (4,2), Mayon (4,0), Michoacan-Guanajuato (4,0)

Class 3 to 3.9 (7 volcanes):

Villarica (3,9), Bulusan (3,9), Cotopaxi (3,7), Aso (3,6), Tarumae (3,4), Gamalana (3,4), Taal (3,0)

Class 2 to 2.9 (19 volcanoes):

Pico de Orizaba (3,0), Tungurahua (2,9), Piton de la Fournaise (2,8), Guagua Pichincha (2,7), Mt Cameroon (2,7), Asama (2,7), Llaima (2,6), Nyamuragira (2,6), Karangetang (2,6), Hekla (2,5), Agung (2,4), Sinabung (2,4), Karthala (2,4), Lokon-Empung (2,1), Avachinski (2,1), Galunggung (2,1), Acatenango (2,0), Bardarbunga (2,0), Semeru (2,0)

Class 1 to 1.9 (18 volcanoes):

Galeras (1,9), Colima (1,9), Purace (1,9), Telica (1,7), Koriakski (1,7), Fuji (1,7), San Salvador (1,6), Tacana (1,6), Nevado del Huila (1,6), Sundoro (1,5), Caminguin (1,4), Soufrière Guadeloupe (1,3), Santorini (1,3), Teide (1,2), Awu (1,2), Askja (1,1), Banda Api (1,1), Mt Pelée (1,0)

Class 0.1 to 0.9 (25 volcanoes):

Santa Ana (1,0), Vestmannaeyjar (1,0), El Chichon (0,9), Makian (0,9), Manam (0,9), Soufrière St Vincent (0,8), Savo island (0,7), Ubinas (0,6), Almolonga (0,6), Fogo (0,5), Ulawun (0,5), Cumbre Vieja (0,5), Nevado del Tolima (0,5), Guntur (0,5), Papandayan (0,5), Unzen (0,5), Bam island (0,4), Ceboruco (0,3), Cosiguina (0,3), Dona Juana (0,3), Turrialba (0,3), Okataina (0,3), Huaynaputina (0,2), Cumbal (0,1), Ijen (0,0)

Class 0 (17 volcanoes):

Mt Rainier (0), Karymsky (0), Stromboli (0), Campi Flegrei (0), Dukono (0), Ibu (0), Kliuchevskoi (0), Dempo (0), Sangay (0), Kanlaon (0), Lengai (0), Copahue (0), Kikai (0), Suwanosejima (0), Marapi (0), Reventador (0), Ruapehu (0)

However, a more precise scale is this one (I created it in 2016 and it should replace the older one.):

dangerosity = (number of "Erupted Volume Index = 0" eruptions per year) * (number of estimated deaths per "EVI = 0" eruption) + (number of "EVI = 1" eruptions per year) * (number of estimated deaths per "EVI = 1" eruption) + ... + (number of "EVI = 8" eruptions per year) * (number of estimated deaths per "EVI = 8" eruption)

Note that the EVI (Erupted Volume Index) is the same as VEI, but it also includes the volcanic materials that don't come from an explosion.

To estimate the number of deaths per "EVI = x" eruption, we evaluate the different risks that could cause fatalities (lava flows, toxic gases, pyroclastic flows, lahars, ashfall...), the probability that one person would die when he faces those risks and the number of people concerned by each of those risks.