Hurricane Maria generated landslides in Puerto Rico, devastating infrastructure and property, hampering rebuilding and recovery efforts by changing drainage systems, and increasing risks from future storms to crews on the ground.
Landslide and Debris Flow Survey
Hurricane Maria hit the island of Puerto Rico on 20 September 2017 and triggered more than 40,000 landslides in at least three-fourths of Puerto Rico’s 78 municipalities. The number of landslides that occurred during this event was two orders of magnitude greater than those reported from previous hurricanes. Our evaluation of landslide distribution shows that while landslides occurred throughout most of Puerto Rico’s mountainous interior, landsliding was particularly severe in five distinct areas.
Most landslides were shallow, but there were some deeper ones in some cases. These occurred before, during, and after flooding, and many of them became long runout debris flows. Steep slopes in hilly and mountainous regions were particularly impacted by landslides due to already-wet soils. Satellite-based soil moisture data collected between 26 September and 8 October 2017 allowed a rapid assessment, and the results matched well with the distribution of landslides. In the future, the use of soil moisture data could enable assessments of regional landslide susceptibility prior to hurricanes or extreme precipitation events.
(edited from Bessette-Kirton, Erin K., Corina Cerovski-Darriau, William H. Schulz, Jeffrey A. Coe, Jason W. Kean, Jonathan W. Godt, Matthew A. Thomas, and K. Stephen Hughes, 2018, Landslides Triggered by Hurricane Maria: Assessment of an Extreme Event in Puerto Rico, Geol. Soc. Amer. Today.)
USGS Data Release – Map data showing concentration of landslides caused by Hurricane Maria in Puerto Rico