Historical tsunami
A tsunami documented to occur through eyewitness or instrumental observation within the historical record.

The most recent geologic era; from about 10,000 years ago to the present. The Holocene is the latest epoch of the Quaternary period.

Hot Spot
A volcanic center, 100 to 200 km in diameter that has existed for a minimum of tens of millions of years. It is thought to be the surface expression of a persistent rising plume of hot mantle material. Hot spots are not linked to arcs and may not be associated with ocean ridges.

Hot-spot Volcanoes
Volcanoes related to a persistent heat source in the mantle.

The point at which within the earth where an earthquake rupture starts. Also commonly referred to as the focus.

Hazard maps (volcanic)
A volcanic hazard map is a graphical representation of the areal distribution of the various hazards to which the territory on and around a volcano would be exposed in the event of a renewal of volcanism, generally in the short to mid term; i.e. in years or tens of years. It is the basic tool used by civil authorities to evaluate volcanic risk and plan risk mitigation actions.