A volcano's pulse

Before the 1995 Soufrière Hills eruption began, there had been seismic crises approximately every 30 years since the late 1890s; each crisis lasted months to years and involved thousands of small earthquakes. In 1935, some earthquakes were large enough to cause damage to buildings in the capital Plymouth and there was real concern that an eruption was imminent. These seismic crises were later interpreted as pulses of magma trying, but failing, to reach the surface. A final seismic crisis began in 1992, and by November 1995 fresh lava had reached the surface and began to form a dome in the volcano’s summit crater. The eruption has since been characterised by pulsatory activity on a range of different timescales.