What phenomenon can tsunamis result from?

Tsunamis primarily result from significant geological events that involve the rapid displacement of large volumes of water. One of the most common causes is earthquakes occurring on reverse or thrust faults, particularly in subduction zones. These zones are areas where one tectonic plate is being forced under another, often creating intense seismic activity. When such an earthquake happens underwater, the abrupt vertical movement of the seafloor can displace a massive amount of water, generating waves that can travel across entire ocean basins.

While volcanic eruptions can also lead to tsunamis, particularly those that involve landslides or explosive activity causing water displacement, they are less common compared to earthquakes in subduction zones. Heavy rainfall does not directly generate tsunamis; rather, it may contribute to flooding events or smaller waves but does not cause the large, devastating waves characteristic of tsunamis. Earthquakes on normal faults could create local waves but lack the same potential for large-scale tsunami generation as reverse or thrust fault earthquakes in subduction zones, which have the capacity for significant vertical displacement along tectonic plate boundaries.