Which mechanism causes increased lahar risk downstream from a stratovolcano after a heavy rainfall event?

💡 Explanation

During a heavy rainfall event, glacier meltwater combines with loose volcanic ash and debris on the slopes of a stratovolcano causing debris flow, increasing lahar hazards. Therefore glacier meltwater mobilizing loose ash is the correct consequence, rather than destabilization, weakening, or uplift, which involve different triggers.

• Which process is initiated at high elevations following glacial retreat from a cirque basin that exposes fractured bedrock?
• Which process primarily drives the formation of a stepped or terraced cirque morphology in mountainous regions?
• Which risk increases when construction restricts seasonal overflow on an alluvial fan?
• Which effect limits phytoplankton blooms despite nutrient-rich upwelling in certain ocean regions?
• Which volcanic outcome characterizes subduction beneath continental crust?
• Which outcome commonly results following extensive groin construction inhibiting longshore sediment transport near barrier islands?