Table 1.3.

Precursory activity prior to extrusive phases

PhasePrecursory periodImmediate precursorDate of extrusion*Extrusion rate (m3 s−1)
14 months of ash venting15 November 19950.2
18 July 1995–14 November 1995
216 months? of ash venting/explosions27 November 19991.5
3–9 November 1999 hybrids and pumice explosions
33.5 months of ash venting and explosions, plumes (10 km), fine phreatic ash1 August 20050.04
15 April–30 July 2005
4a3 months of ash venting/explosionsVT/hybrid swarm, 29 July 2008, pumice explosion (12 km)1–14 August 20080.01
5 May–27 July 2008
4b3 December 2008, non-pumice explosion10 December 200810
54 days9 October 2009c. 10
5–7 October 2009, VT swarm, explosions, plumes (6 km)
  • *Dates are those when new lava was first observed, actual first extrusion might be earlier because of cloud cover.

  • Monthly average of lava extrusion rate following restart.