Daniel S. Brothers Peter J. Haeussler Robert C. Witter Jenna C. Hill Natalia A. Ruppert M. Jadamec Jeffrey T. Freymueller Drake Moore Singleton 2025 <p><span>Strong ground motion from intraslab earthquakes, which do not produce primary paleoseismic evidence, may initiate gravity-driven turbidity flows in subaqueous basins. The resulting deposits (turbidites) can provide a paleoseismic proxy if the conditions that initiate these flows are known. To better constrain the initiating conditions, we use two recent intraslab earthquakes in southcentral Alaska, the&nbsp;</span><i>M</i><span>&nbsp;</span>_w<span>&nbsp;7.1 30 November 2018 Anchorage earthquake and the&nbsp;</span><i>M</i><span>&nbsp;</span>_w<span>&nbsp;7.1 24 January 2016 Iniskin earthquake, as calibration events. Through a multilake investigation, we document the occurrence, or the absence, of earthquake-generated turbidity flows from these two events. Both earthquakes are recorded by centimeter-scale turbidites that can be differentiated from climatically generated deposits, as well as other seismic sources based on deposit thickness, sedimentological properties, and deposit age. We show that a Modified Mercalli Intensity (MMI) of ∼V–V1/2 is the minimum shaking intensity required to generate localized sediment remobilization from deltaic slopes, and an MMI of ∼V1/2 is required to produce a deposit of sufficient thickness that a seismic origin can be confidently assigned. The documentation of seismically generated deposits in quick succession (∼2 years) with diagnostic features highlights the utility of using recent earthquakes as calibration events to investigate the subaqueous response to strong ground motion.</span></p> application/pdf 10.1002/9781394195947.ch14 en American Geophysical Union Constraining the earthquake recording threshold of intraslab earthquakes with turbidites in southcentral Alaska’s lakes and fjords chapter