Complex sentence: The 1787 Boricua (Puerto Rican) earthquake was estimated to have been a Magnitude 8.0-8.5, evidence of such quake is located somewhere off the north coast of Puerto Rico.
Split into simpler sentences: The 1787 Boricua (Puerto Rican) earthquake struck just off the Puerto Rican island. It was estimated at magnitude 8.0-8.5, evidence of such quake is located somewhere off the north coast of Puerto Rico.