Relating Dike Geometry and Injection Rate in Analogue Flux-Driven Experiments

Dikes feed most eruptions, so understanding their mechanism of propagation is
fundamental for volcanic hazard assessment. The variation in geometry of a
propagating dike as a function of the injection rate remains poorly studied. Here we
use experiments injecting water into gelatin to investigate the variation of the thickness,
width and length of a flux-driven dike connected to its source as a function of the injection
time and intruded volume. Results show that the thickness of vertically propagating dikes
is proportional to the injection rate and remains constant as long as the latter is constant.
Neither buoyancy nor injected volume influence the thickness. The along-strike width of
the dike is, however, proportional to the injected volume. These results, consistent with
the inferred behavior of several dikes observed during emplacement, open new
opportunities to better understand how dikes propagate and also to forecast how
emplacing dikes may propagate once their geometric features are detected in real-time
through monitoring data.