In geographical studies of natural hazards, a clear distinction is made between a 'natural event' and a 'natural hazard' based on its intersection with human systems. Which of the following scenarios is classified strictly as a natural event rather than a natural hazard?
A magnitude 7.87.87.8 earthquake occurring along the Gakkel Ridge in the Arctic Ocean, with no human populations, shipping lanes, or infrastructure within its radius of impact.
A high-magnitude volcanic eruption on an uninhabited Pacific island that lies directly beneath a major international commercial aviation flight path.
A submarine landslide in the Gulf of Mexico that triggers a localized tsunami threatening offshore deepwater drilling rigs.
A seasonal river flood in an agricultural valley where local communities have successfully adapted by constructing elevated stilt homes.
