Final answer:
In a subduction plate boundary earthquake, the rapid movement of an oceanic plate beneath another can displace water and trigger a tsunami, occurring at convergent boundaries.
Step-by-step explanation:
In a subduction plate boundary earthquake, the scenario described involves a tectonic plate lifting another into the sea, causing the upper plate to move rapidly and displace a significant volume of sea water. This process, when the mound of displaced water collapses and rushes towards land, is called a tsunami. Such events often occur at convergent boundaries, where an oceanic plate subducts beneath a continental plate or another oceanic plate, leading to various geological phenomena including earthquakes, mountain formation, and volcanic activity.
In a subduction plate boundary earthquake, the upper tectonic plate is forced beneath another plate into the mantle. When this happens, the upper plate can move meters in seconds, pushing sea water up. The mound of water that is pushed up when the upper plate lifts is called a tsunami. When this mound of water collapses, it sends a huge volume of water speeding towards land, resulting in a tsunami.