Which consequence results when thick tephra accumulates rapidly?

💡 Explanation

Slope instability and subsequent lahars occur because rapid tephra accumulation increases pore water pressure, reducing shear strength through effective stress reduction. This triggers debris flows, therefore lahars are more likely, rather than gas release changes.

• Which soil horizon develops reduced fertility when intense equatorial rainfall raises the leaching limit?
• Which risk increases when barrier islands retreat landward?
• Which mechanism causes increased tsunami amplitude following an earthquake where thrust fault rupture propagates towards the coast?
• Which mechanism is triggered when differential stress exceeds static friction along an existing fault line?
• Which outcome occurs when sediment supply surpasses transport capacity in stream outflow onto a low-gradient surface?
• Which risk increases for communities protected by artificial levees during intense, prolonged rainfall events?