The province lies within the Philippine Fault System. The major fault lines traverse the municipalities of Sogod, Libagon, Saint Bernard and San Juan to Panaon Island. Based on Mines and Geosciences Bureau Region 8 data, these areas had experienced strong earthquakes in 1907 and 1948 with a magnitude of 6.9 and on July 5, 1984 with a 6.4 scale. The Mines and Geosciences Bureau warned that Southern Leyte's natural and geological features make it susceptible to landslides and floodings. The affiliated group stated that there are four contributory reasons: unusually heavy rains; numerous faults and badly broken rocks; steep slopes; and absence of effective vegetative cover.