The Philippine Institute of Volcanology and Seismology (Phivolcs) believes revisions may be needed in the geohazard maps for Bohol and neighboring provinces. Phivolcs said Tuesday's quake may have been caused by a previously unknown fault system which became more evident as they monitored aftershocks. But speaking to ANC, Ishmael Narag, officer-in-charge of the agency's seismology division, clarified current geohazard maps are still reliable and should be consulted in reconstruction efforts. ANC Dateline Philippines, October 19, 2013