Question: when did the largest swarm of earthquakes at long valley take place
[{'answer': 'May 1980', 'provenance': [{'wikipedia_id': '46811', 'title': 'Long Valley Caldera', 'start_paragraph_id': 22, 'start_character': 3, 'end_paragraph_id': 22, 'end_character': 11, 'bleu_score': 1.0, 'section': 'Section::::Geology.:Recent activity.\n'}]}, {'provenance': [{'wikipedia_id': '46811', 'title': 'Long Valley Caldera', 'start_paragraph_id': 22, 'start_character': 0, 'end_paragraph_id': 22, 'end_character': 725, 'bleu_score': 0.9542174745769371, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12664961228820531258}, 'section': 'Section::::Geology.:Recent activity.\n'}]}]