Much of the land on the Cayman Islands is low-lying, particularly on Grand Cayman, most of which reaches little more than 1 m above sea level. However, on Cayman Brac an impressive east-west limestone ridge known as The Bluff rises to 43 m. The whole region is seismically active due to the close proximity of the Caribbean plate boundary; minor earthquakes occur frequently in the islands, although these do not usually cause significant damage.