The solidification of volcanic rock-like materials using cohesive zone models and finite element method

This paper presents a two-dimensional numerical model for the solidification of volcanic rocks under water. The method combines cohesive zone models and finite element analysis to simulate thermal cracking, water ingression, and phase change during lava cooling. An empirical law estimates the convective heat flux through fractures based on their geometry and distribution. Simulations capture the formation of columnar joints, crack propagation, and transitions from conduction-dominated to convection-dominated cooling. Results are validated against observations from Kı̄lauea Iki and Grímsvötn, demonstrating good agreement with field data. The work establishes a validated framework for modelling solidification of volcanic rock-like materials under water, and could subsequently be extended to simulate a variety of geometries and cooling conditions, providing deeper insights into key geological processes. • New numerical model simulates lava solidification with thermal cracking. • Combines cohesive zone modelling and finite element method for accuracy. • Captures two crust evolution phases: conduction, then convection-conduction balance. • Results agree well with experiments on solidification speed and crack spacing.