Understanding the seismic signals produced by volcanoes are particularly challenging due to the following issues:

• very heterogeneous material, e.g. unconsolidated, loose ash, rock fragments,
  lava, porous tuff, etc.
• pronounced topographic features
• complexity of the source process and uncertainty in the underlying source mechanism

Furthermore, data collection at active volcanoes can be difficult and therefore modeling approaches that consider the complexity of the seismic signal occurring in volcanoes can help to understand the physical processes of tremor and eruptions.

Infrasound measurements in the vicinity of a volcanic crater, along the slopes and the surrounding region started to provide additional data that might help to put more constraints to the source process. Therefore, modeling of the seismo-acoustic wave coupling is an important issue that poses difficulties for many numerical schemes due to the large impedance contrast of volcanic material and air along a geometrically complex free surface topography.