Which phenomenon causes mantle upwelling beneath the overriding plate where an oceanic plate subducts at an increasing angle?

💡 Explanation

When an oceanic slab subducts at an increasing angle, slab rollback occurs because the slab pulls itself downward, inducing suction in the asthenosphere and causing mantle upwelling. Therefore asthenosphere suction results, rather than crustal loading, hydrothermal circulation, or accretion which involve different crustal processes.

• Which effect increases as plastic debris accumulates in ocean gyres experiencing stratification?
• Which risk increases with prolonged water saturation of an aging earthen levee structure?
• Which geomorphological outcome occurs when carbonic acid exceeds limestone dissolution limits?
• Which risk increases when thawing permafrost causes widespread solifluction on Arctic slopes used for pipeline construction?
• Which mechanism causes deep-water oxygen depletion in poorly mixed fjords with high organic matter input?
• Which outcome occurs when pyroclastic density currents encounter water?