Which risk increases when lava cools rapidly subaerially?

💡 Explanation

Increased surface area from rapid cooling promotes fracture formation via thermal contraction; this results in uneven, blocky A'a formation because the differential cooling stresses fragment the surface unevenly, therefore A'a lava forms rather than smoother pahoehoe lava.

• Which outcome occurs more slowly as agricultural topsoil undergoes drastic reduction in arthropod populations?
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• Which outcome is directly enhanced due to differential cementation?
• Which mechanism increases lahar hazard during and after stratovolcano eruption sequences?
• Which outcome occurs when excessive groundwater extraction weakens sandstone cliffs?
• Which outcome is most likely downstream when unusually strong Benguela upwelling occurs off Namibia?