although the more explosive, lava-fountaining stage may last only a few days to a week, explosion-dominated eruptions can continue for weeks to months, producing large, voluminous silicate lava flows. a major eruption in 1997 from a fissure north-west of pillan patera produced more than of fresh lava over a - to -month period, and later flooded the floor of pillan patera. observations by "galileo" suggest lava coverage rates at pillan between per second during the 1997 eruption. the pillan flow was found to be thick, compared to the thick flows observed at the inflated fields at prometheus and amirani. similar, rapidly emplaced lava flows were observed by "galileo" at thor in 2001. such flow rates are similar to those seen at iceland's laki eruption in 1783 and in terrestrial flood basalt eruptions.