Retrospective analysis of uncertain eruption precursors at La Soufrière volcano, Guadeloupe, 1975–77: volcanic hazard assessment using a Bayesian Belief Network approach

Table 1 Eruptive chronology of La Soufrière in the last 9000 years, with calibrated radiocarbon dates (CE: common era and BCE: before common era) from Boudon et al. ( 1988 ); Komorowski et al. ( 2005 ; 2008); Boudon et al. ( 2007 and 2008); Siebert and Simkin ( 2002–2011 )

Start date	Type	Description
6535 BCE	E	Edifice collapse - not magmatic, not explosive
4000 BCE ?	M	VEI 2 explosive Strombolian
3600 BCE ?	M	VEI 2 explosive Vulcanian
3360 BCE	M	VEI 3 magmatic dome eruption, possibly explosive
2400 BCE ?	E	Edifice collapse - not magmatic, not explosive
1625 BCE	M	VEI 3–4 explosive magmatic with edifice collapse and blast (possible cryptodome?)
1400 BCE	M	VEI 3–4 explosive magmatic with edifice collapse and blast (cryptodome)
1065 BCE ?	E	Edifice collapse - not magmatic, not explosive
980 BCE	M	VEI 3 magmatic dome eruption, possibly explosive
465 BCE	M	VEI 3 explosive magmatic dome eruption with edifice collapse and blast
310 CE	M	VEI 2 explosive Strombolian
605 CE	E	Edifice collapse - not magmatic, not explosive
1530 CE	M	VEI 2–3 explosive Subplinian and dome magmatic eruption with edifice collapse
1635 CE ?	M	VEI 2 explosive magmatic, possibly Vulcanian
1690 CE	P	VEI 1 Phreatic - not magmatic but explosive (Komorowski et al. 2005)
1797 CE	P	VEI 1 Phreatic - not magmatic but explosive (Komorowski et al. 2005)
1812 CE	P	VEI 1 Phreatic - not magmatic but explosive (Komorowski et al. 2005)
1836 CE	P	VEI 1 Phreatic - not magmatic but explosive (Komorowski et al. 2005)
1956 CE	P	VEI 1 Phreatic - not magmatic but explosive (Komorowski et al. 2005)
1976 CE	F	VEI 1 failed (still-born) magmatic explosive (Komorowski et al. 2005)

Events are classified as non-magmatic, non explosive edifice collapses (E); magmatic explosive (M); non magmatic but explosive phreatic events (P), or failed magmatic (F), as in 1976. A question mark indicates the eruption date is uncertain. The last confirmed major magmatic eruption of La Soufrière was 1530 AD (Boudon et al. 2008and Komorowski et al. 2008a 2008b). Phreatic eruptions (identified from historic reports as well as stratigraphic evidence) appear to be more frequent in the last 400 years, however there is significant bias in the catalogue. Evidence of less energetic eruptions before settlement on the island is likely to have been missed, destroyed during larger magmatic events, or poorly preserved in the stratigraphic record. This is also the case for low magnitude magmatic eruptions (VEI 2) as shown by Legendre (2012).

ISSN: 2191-5040