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Afternoon Update for Puerto Rico - January 8, 2020

January 8, 2020

Earthquake Aftershock Forecast

relative seismicity
Figure shows a timeline of seismicity during earthquake sequence in Puerto Rico in December 2019 (weeks 49-52) and early January 2020 (weeks 1-2)  versus the magnitude of each earthquake. Each symbol is an earthquake, sized by magnitude, which is also represented on the y-axis.

Today's forecast [as of 03:24:26 EST] estimates that over the next 1 Week there is a 4 percent chance of one or more aftershocks that are larger than magnitude 6.4. It is highly likely that there will be many smaller earthquakes (M>3) over the next 1 Week. Magnitude 3 and above events are large enough to be felt near the epicenter. The rate of aftershocks will decline over time, but a large aftershock can increase the numbers again, temporarily.

Our forecasts change as time passes due to decline in the frequency of aftershocks, larger aftershocks that may trigger further earthquakes, and changes in forecast modeling based on the data collected for this earthquake sequence.