Igneous rocks
One of the three main groups of rocks (the others being sedimentary and metamorphic). Igneous rocks originate from magma, and may be either extrusive or intrusive.

The rock formed by the widespread deposition and consolidation of ash flows and pyroclastic flows.

The degree of shaking at a particular location during an earthquake

Intensity Map
A map showing intensity at different locations during an earthquake.

Intensity Scales
Scales from which the intensity of an earthquake at a particular location can be determined from its effects on people, buildings, ground, vegetation etc.

Inundation area
The area flooded with water by a tsunami.

Processes that occur between the earth’s tectonic plates.

Processes that occur within the earth’s plates.

The term refers to igneous rock mass so formed within the surrounding rock. Also refers to the process of emplacement of magma in pre-existing rock.

Isoseismal (line)
Is a contour or line on a map that connects points of equal intensity for a particular earthquake.

Isoseismal map
A map showing the distribution of intensity across a region for a particular using isoseismal lines