Final answer:
Tsunamis do not cause increased volcanic activity, but they can cause coastline erosion, contaminated water supplies, disease, and fires.
Step-by-step explanation:
Of the given options, increased volcanic activity is NOT an effect that can be caused by tsunamis. Tsunamis are usually triggered by earthquakes or volcanic eruptions, and they occur in the ocean. They create powerful waves that can cause coastline erosion, contaminated water supplies, disease, and fires.
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