Neither. Pahoehoe and a'a are both basaltic lavas (mafic composition). Soufreier Hills erupts andesitic material (intermediate composition). This material took the form of ash and pumice forming pyroclastic flows (which are more like avalanches) rather than lava flows.
Pahoehoe comes from an explosive eruption, whereas AA comes from quiet eruptions.
The differences are that Pahoehoe produces fast moving lava; Aa produces slower moving lava. The kind of eruption that produces these types of lava is a quiet eruption.
Quiet eruptions
Lava flows of pahoehoe and aa indicate that the eruption was effusive ("quiet") rather than explosive, or only very mildly explosive.
Pahoehoe and AA lava are produced by quiet eruptions. This means that instead of a blast or explosion, the lava just flows out of the volcano. Pahoehoe lava is hot and flows quickly. AA lava is cooler in temperature and doesn't flow as quickly.
They indicate that an eruption is effusive rather than explosive.
They indicate that an eruption is effusive rather than explosive.
Lava flows of pahoehoe and aa indicate that the eruption was effusive ("quiet") rather than explosive, or only very mildly explosive.
Lava flows of pahoehoe and aa indicate that the eruption was effusive ("quiet") rather than explosive, or only very mildly explosive.
Aa and pahoehoe are both produced from basalt lava eruptions. The difference in the two being a difference in temperature. Pahoehoe is a hotter flow, moving more smoothly before cooling into rope-like structures. Aa is a bit cooler, forming solid chunks, but continuing to move.
The difference between Pahoehoe lava and AA lava is that pahoehoe lava is smooth and AA lava is jagged.
No, pahoehoe and aa lava are typically produced during non-explosive eruptions. Pahoehoe lava has a smooth, ropey texture, while aa lava is rough and jagged. Explosive eruptions typically produce ash, pyroclastic flows, and lava domes.