I think the word you're looking for is epicenter. The uncertainty is because that's actually the surface location directly above the hypocenter or focus of an earthquake, which may not have been what you meant.
epicenter.
The epicenter.
The block of rock below a fault is the "footwall" if you are referring to geology/earthquake terms.
origin
the origin
The Epicenter.
The point of origin of an Earthquake within the earth is known as the hypocentre. It can also be called the focus.Directly above this on the surface is the earthquake's epicenter.
The point of origin of an earthquake is called the hypocentre or focus. The epicenter is the point on the surface directly above the focus.
This is known as the focus or hypocentre of an earthquake.
It is a plane surface with an origin and a pair of orthogonal axes. The location of any point in the plane is given by an ordered pair of coordinates: the abscissa (distance to the right of the origin) and the ordinate (distance in the vertical direction from the origin).
A location is the position which is usually measure in terms of a fixed point of reference, which is called the origin. In n-dimensional space the location may be defined in terms of distances from origin along orthogonal axes (n axes), or in terms of distance and direction (one measure of distance and n-1 angles). Location on the surface of a sphere, for example the earth, can be defined by only two angles (the latitude and longitude) and no distance because the distance is implied (radius of the earth).
The point of origin of an Earthquake within the earth is known as the hypocentre. It can also be called the focus.Directly above this on the surface is the earthquake's epicenter.