Question: what is the biggest volcano in the us
[{'answer': 'The Island Park Caldera', 'provenance': [{'wikipedia_id': '379647', 'title': 'Yellowstone Caldera', 'start_paragraph_id': 7, 'start_character': 594, 'end_paragraph_id': 7, 'end_character': 617, 'bleu_score': 1.0, 'section': 'Section::::Volcanism at Yellowstone.\n'}]}, {'provenance': [{'wikipedia_id': '379647', 'title': 'Yellowstone Caldera', 'start_paragraph_id': 7, 'start_character': 4, 'end_paragraph_id': 7, 'end_character': 1098, 'bleu_score': 0.965525482650837, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4177619058358296650}, 'section': 'Section::::Volcanism at Yellowstone.\n'}]}]