2020 Southwest Puerto Rico Earthquake Sequence (Jan 29, 2020)
The U.S. Geological Survey has released a report on the potential duration of aftershocks of the 2020 Southwest Puerto Rico earthquake sequence (series) to guide public policy decisions, other actions, and help people stay safe and care for themselves and each other.
i) AFTERSHOCK FORECAST*
Aftershocks are normal and some will be larger than others, but there will be fewer over time.
earthquakes will occur daily for months, and then weekly for years.
YEARLY CHANCE OF M5+currently >99% and will stay over 50% for 3 – 10 years
YEARLY CHANCE OF M6+currently 50% and will stay over 25% for 3 months – 3 years
YEARLY CHANCE OF M7+currently 8% and will stay over 5% for 1 – 10 months
YEARLY CHANCE OF M7+will stay over 1% for 2 – 10 years
The yearly chance is the likelihood of an earthquake happening any time within a year-long period. Future aftershocks will be located in the same area as past events. These aftershocks do not change the risk on other parts of Puerto Rico.
* The results in this report are based on the current behavior (as of January 17, 2020) of this aftershock sequence and may need to be modified if that behavior changes, including if a larger earthquake occurs.
Although earthquakes are normal in Puerto Rico they can be unsettling. Feeling anxious or stressed?
La Línea PAS (Primera Ayuda Sicosocial) Crisis Counselors
A special thanks to our Advanced National Seismic System (ANSS) partner, the Puerto Rico Seismic Network (PRSN) at University of Puerto Rico at Mayaguez. Background: Building destruction in Puerto Rico, January 2020.
i) Forecast Report at www.usgs.gov/pr-forecast-2020
Science for a Changing World
Federal Emergency Management Agency (FEMA)
U.S. Department of the Interior
U.S. Geological Survey
Magnitude 6.4 Earthquake in Puerto Rico
Links to forecasts and scenerios (below) will continue to be updated, however, text in this story will not be updated unless there is significant change to the aftershock behavior or to the USGS response to the earthquake.
Potential Duration of Aftershocks of the 2020 Southwestern Puerto Rico Earthquake
Aftershocks (earthquakes clustered spatially and chronologically near the occurrence of a causative earthquake) are ongoing in southwestern Puerto Rico after a series of earthquakes, which include a magnitude 6.4 earthquake that occurred near Barrio Indios, Guayanilla, on January 7, 2020, and affected the surrounding area. This report estimates the expected duration of these aftershocks by incorporating observations of aftershocks as of January 17, 2020, into a well-established statistical model of how earthquake sequences behave. Aftershocks will persist for years to decades, although with decreasing frequency, and earthquakes will likely be felt on a daily basis for up to several months. These estimates have significant uncertainty owing to different scenarios of how the earthquake sequence may evolve over time and could also change if a new large aftershock occurs. This report also estimates the amount of time remaining until the annual probability of magnitude 5, 6, and 7 or greater aftershocks—which could cause additional damage—decreases to 50, 25, 10, 5, and 1 percent. As of this writing, the chance of having a magnitude 6 or greater earthquake within a given year, going forward, will not fall below 25 percent for another 3 months to 3 years. The chance of having a magnitude 5 or greater earthquake will not fall below 25 percent for a decade or more. The aftershocks discussed in this report would be located in the same general area as the aftershocks that have already occurred. Our results do not imply a change in the risk of earthquakes in other parts of Puerto Rico.