LAUSR

On 14 August 2021, the moment magnitude (Mw) 7.2 Nippes earthquake in Haiti occurred within the same fault zone as its devastating 2010 Mw 7.0 predecessor, but struck the country when field access was limited by insecurity and conventional seismometers from the national network were inoperative. A network of citizen seismometers installed in 2019 provided near-field data critical to rapidly understand the mechanism of the mainshock and monitor its aftershock sequence. Their real-time data defined two aftershock clusters that coincide with two areas of coseismic slip derived from inversions of conventional seismological and geodetic data. Machine learning applied to data from the citizen seismometer closest to the mainshock allows us to forecast aftershocks as accurately as with the network-derived catalog. This shows the utility of citizen science contributing to our understanding of a major earthquake. Description Homebound seismology The 2021 Nippes earthquake in Haiti destroyed up to 140,000 homes and killed several thousand people. Despite the large seismic hazard there, Haiti only has a few high-quality seismic stations. Calais et al. show that a low-quality seismic network hosted in the homes of volunteers is capable of providing important data for characterizing an earthquake and its aftershocks (see the Perspective by von Hillebrandt-Andrade and Vanacore). The citizen seismic network was particularly important for identifying and determining the likelihood of damaging aftershocks, which is vital information for those responding to the destructive mainshock. —BG Low-cost seismic stations can help to characterize an earthquake and its aftershocks.