The V4 engine has proven itself highly reliable, with few known faults.

Large fractions of the settled delta are in earthquake liquefaction zones above known active faults.

The presumed epicenter of the 1843 earthquake is not, however, associated with any known fault.

West of Delphi, he found that it linked up to a known fault.

Virtually all of the known faults have not been active for perhaps 90 million years or more.

Also, the locations of the known faults are not well determined at earthquake depths.

Inspection validation is used to test inspectors, procedures and equipment by way of trials on test specimens with known faults.

And there were two other known faults in the unit too.

Even the known faults are poorly located at earthquake depths.

It is difficult to determine if a known fault is still active and could slip and cause an earthquake.