Definition: In this task, a passage will be given and the goal is to identify an event from the passage. An event is defined as a single word representing something that happened, is happening, or may happen. An event can be factual or hypothetical, positive or negative, certain or uncertain. While most events are based on verbs, an event can also be based on a noun (ex. storm, snow, rainfall) or a copula verb (is, was, been, etc.). The event must not be a pronoun or an adjective. For noun events with multiple words, use the last word in the phrase as event.
Input: Passage: Confrontations among Catholic protesters, Protestant marchers and the police have provoked widespread violence in Northern Ireland for the past three summers. The crucible is Portadown, 30 miles (50 kms) southwest of Belfast, where Orangemen march each July from their rural church back downtown _ through the town's main Catholic area.

is