Connectivity and hydrological efficiency dynamics at active volcanoes, Mexico.

Area of Science:

• Geomorphology
• Volcanology
• Hydrology

Background:

• Topographic complexity influences sediment transfer, with high connectivity potentially causing extreme events like lahars in volcanic regions.
• Volcanic and anthropogenic activities significantly impact sub-basin behavior and sediment transport dynamics.

Purpose of the Study:

• To analyze sub-basin activation-deactivation by examining changes in connectivity and hydrological efficiency.
• To investigate these changes in two active Mexican volcanic zones: Volcán de Colima and Popocatépetl volcano.

Main Methods:

• Calculation of the joint index of connectivity (ICJ) and lateral hydrological efficiency index (LHEI).
• Application of classification trees to identify critical thresholds for sub-basin behavior modification.
• Analysis of basins affected by eruptive activity and co-seismic landslides.

Main Results:

• Identification of eleven activated sub-basins (3.82 km²) at Volcán de Colima and fifteen (3.77 km²) at Popocatépetl volcano.
• Determination of critical land cover/use thresholds for high LHEI values and sub-basin behavior changes.
• New active areas were identified through the integrated analysis of connectivity and hydrological efficiency.

Conclusions:

• The interplay between volcanic hydrogeomorphology and socio-economic activities shapes sediment transport.
• Understanding these newly identified active areas is crucial for future hazard and risk assessment in volcanic regions.