Tsunami Deposits in the Guerrero Seismic Gap, Mexico: Insights from Location Analysis, Earthquake and Tsunami Models, and Proxy Dataset

Globally, the most significant tsunamigenic earthquakes have occurred along subduction zones. Catastrophic events surpassing magnitude 9, such as those witnessed in Chile, Sumatra, and Japan, have occurred in regions where instrumental records of similar events are lacking. Despite the absence of such occurrences along the 1000-kilometer-long Mexican subduction zone, historical and geological evidence strongly suggests the likelihood of a magnitude 8.6 tsunamigenic earthquake. However, the Guerrero seismic gap has remained devoid of high-magnitude earthquakes for over a century. In this study, we present findings from analyses of sediment grain size, geochemistry, microfossils, magnetic properties, and radiometric and optically stimulated luminescence dating conducted along the Guerrero coast. Our research provides compelling evidence of a 2000-year history of significant tsunamis triggered by potentially large earthquakes. Numerical modeling reinforces our conclusions, pointing to a magnitude >8 event occurring around the year 1300 in the Guerrero seismic gap. This evidence underscores the critical importance of evaluating earthquake and tsunami potential through long-term evidence and instrumental observations along subduction zones globally. Additionally, this dataset includes the locations of study sites, proxy data, and earthquake and tsunami models. Source data: Grain size - Figure S1 Geochemical - Figure S2 Maximum tsunami wave amplitude - Figure 3d and S4 Maximum tsunami wave amplitude - Figure S5c