COMMA SPLICE

A comma splice occurs when a comma by itself joins independent clauses.
 
            The hurricane intensified, it turned toward land.
            The hurricane intensified, then it turned toward land.

FUSED SENTENCE

A fused sentence occurs when independent clauses are not separated by appropriate punctuation. (It is also known as a run-on sentence or a run-together sentence.)

            The hurricane intensified then it turned toward land.
            The hurricane intensified and it turned toward land.

CORRECTING COMMA SPLICES AND FUSED SENTENCES

Use a period.
 
            The hurricane intensified. Then it turned toward land.

Use a comma plus a coordinating conjunction.

            The hurricane intensified, and it turned toward land.

Use a semicolon if the two clauses are closely related in content..

            The hurricane intensified; its winds increased to 150 miles per hour.

Use a semicolon and a conjunctive adverb.

            The hurricane intensified; therefore the remaining residents left the coast.

Revise one of two independent clauses into a dependent clause.

            As the hurricane intensified, it turned toward land.
             The hurricane intensified as it turned toward land.

Proofreading Tip

Cover all the words on one side of the comma to see if the words remaining constitute an independent clause. Then cover that clause, and uncover all the words on the other side of the comma. If the structures on both sides of the comma are independent clauses, you have written a comma splice and should correct it.