Fig. 3: Physical parameters of the Nisida feeder dyke.
From: Magma chamber failure and dyke injection threshold for magma-driven unrest at Campi Flegrei caldera
a Relationship between dyke aspect ratio (w/L) and overpressure (P0) of the magma in the dyke based on Eq. (18). Density of host rock (ρr) is fixed as 2600 kg m−3. Variations of the dynamic Young’s modulus of the host rock from 1 MPa to 50 MPa are shown. The solid line represents the relationship between w/L and P0 at Ed = 23.4 GPa, as suggested by the velocity of the S-wave (VS) at 1900 m s−1 in the host rock. Error bars denote the error on the w/L ratio and dyke overpressure. b Relationship between dyke aspect ratio (w/L) and vesicularity of magma (p) based on Eq. (5). The calculations are based on two different magma chamber depths (h = 6 km (solid red lines) and 9 km (solid blue lines). The cases of Pe = 0, 2, 4, 6, 8, and 10 MPa are shown for each case. For a depth of 5.7 km, a 9.3 MPa curve is indicated with a dashed black line. The filled triangle indicates the calculated vesicularity of the least-vesiculated bombs of the Nisida eruption, which agrees with the qualitative estimation provided by Arienzo et al.32. The scale at the top of the figure indicates the overpressure corresponding to the dyke aspect ratio (w/L) shown in the horizontal axis of the figure based on Eq. (5) at Ed = 23.4 GPa. Error bars denote the error on the dyke vesicularity and dyke overpressure.
