Abstract
Individual lava flows in flood basalt provinces are composed of sheet
pāhoehoe lobes and the 10-100 m thick lobes are thought to form by
inflation. Quantifying the emplacement history of these lobes can help
infer the magnitude and temporal dynamics of these prehistoric
eruptions. Here we use a phase-field model to describe solidification
and re-melting of sequentially-emplaced lava flows to explore additional
processes that may lead to thick flows. We calibrate model parameters
using field measurements at Makaopuhi lava lake. We vary the thickness
of individual flows and the time interval between eruptions to study the
interplay between thermal evolution, flow thickness and emplacement
frequency. Our theoretical analysis shows that, if the time between
emplacement is sufficiently short, reheating and re-melting may merge
sequentially emplaced flows — making flows appear thicker than they
actually were. Our results suggest that fused flows could be another
mechanism that creates apparently thick lava flows.