Figure 4. Outcrop-to-outcrop siphon behaviour for simulations with two large outcrops.

Outcrop geometries are defined in Table 1. Bottom and left axes indicate outcrop permeability, whereas top and right axes show equivalent transmittance (permeability × outcrop area). Each circle represents results of a single simulation, run to dynamic steady state, delineating the permeability of recharge and discharge ends of the hydrothermal siphon. Colour contours illustrate Q_S (siphon flow rate), whereas solid contour lines and labels delineate F_S (siphon fraction). Note offset between peak values of Q_S and F_S. Simulations within the grey zone did not sustain a hydrothermal siphon.