EarthquakeRecent Chilean earthquakes signal potential for similar future events
Despite the magnitude 8.2 earthquake that hit northern Chile in April 2014, the plate boundary in that region is still capable of hosting shocks of the same size or even greater in the near future, according to new research. Scientists say that while the 2014 Iquique earthquake occurred within the northern Chile subduction zone, it did not fill the entire spatial extent of the gap; thus the potential for a magnitude 8.0 or greater earthquake in northern Chile is still high.
Despite the magnitude 8.2 earthquake that hit northern Chile in April 2014, the plate boundary in that region is still capable of hosting shocks of the same size or even greater in the near future, according to new research presented in Nature (see also this second research article in the same issue of Nature).
The seismic gap theory, which can identify regions of elevated hazard based on a lack of recent seismic activity in comparison with other portions of a fault, had previously identified the northern Chile subduction zone as an area of concern for future magnitude 8.0+ (megathrust) earthquakes The USGS says that scientists from the U.S. Geological Survey and partner agencies show that while the 2014 Iquique earthquake occurred within this gap in activity, it did not fill the entire spatial extent of the gap; thus the potential for a magnitude 8.0 or greater earthquake in northern Chile is still high.
Significant sections of this subduction zone have not ruptured in almost 150 years, so it is likely that future megathrust earthquakes will occur to the south and potentially to the north of the 2014 Iquique sequence in the future.
“As well as revealing interesting aspects of earthquake interactions in this subduction zone, our study indicates that the occurrence of the 2014 magnitude 8.2 event does not mean short-term hazard of large earthquakes in northern Chile has decreased — in fact, while we unfortunately cannot predict the timing of such events, similar-sized or indeed larger earthquakes are possible in the near future,” said USGS research geophysicist Gavin Hayes.
The authors of the second study said the Iquique quake broke about a third of the northern Chile seismic gap, and agreed that “the remaining locked segments now pose a significant increased seismic hazard.”
They put the potential magnitude of such a quake at 8.5.
“The Big One may still be to come,” added University of California geologist Roland Burgmann, who wrote a comment on the studies that was also published by Nature.
— Read more in Gavin P. Hayes et al., “Continuing megathrust earthquake potential in Chile after the 2014 Iquique earthquake,” Nature (13 August 2014) (doi:10.1038/nature13677); and Bernd Schurr et al., “Gradual unlocking of plate boundary controlled initiation of the 2014 Iquique earthquake,” Nature (13 August 2014) (doi:10.1038/nature13681)
