Here's what's happening: The oxygen in the air and the copper in the pennies form an oxide that coats the pennies and makes them look dirty. The acids (usually vinegar - acetic acid) break the copper oxide free from the penny. As we have seen experimentally, acid alone does not clean as well as acid and salt.
The strong ocean currents are undermining both areas causing earthquakes. ... Both areas are on the boundary of active plates, the motion of the plates causes earthquakes.
