Volcanic ash cloud dispersal poses risks; which mechanism governs tephra settling?

💡 Explanation

Tephra settling relies on gravitational settling, because these particles fall due to gravity; air drag reduces velocity; therefore option A, rather than B/C/D occurs under these specific atmospheric flow and density conditions.

• Which landform develops when freeze-thaw cycles and permafrost cause creeping downslope movement of saturated soil?
• Which landform most directly results when persistent wind scours fine particles from desert pavement?
• Which process primarily accelerates cirque formation at high altitudes due to increased freeze thaw weathering?
• Which effect typically occurs in coastal Peruvian fisheries during prolonged El Niño events?
• Which mechanism causes long-term subsidence in sedimentary basins along active strike-slip faults?
• Which outcome increases when mountain stream downcutting declines?