Large, stable, relatively flat expanses of extremely old igneous and metamorphic rocks are

Continental shield

Explanation:

The continental shields are usually referred to those extensively large areas of stable land, within the earth's crust and where there is the presence of the Precambrian crystalline rocks. The rocks of this shield belongs to the Precambrian and Archean age. For example, the Canadian shield.

These shield areas were formed initially during the time of orogenic activity, plate tectonics, where the rocks were eroded and subsequently flattened. These rocks are later covered by the younger sedimentary rocks.

Thus, the continental shield rocks are present in many places on earth and are not much affected during any seismic activity event.