Understanding the processes controlling landslides, earthquakes, volcanic eruptions and tsunamis requires utilizing natural experiments to identify and isolate driving factors. How do climate and tectonics interact to determine the susceptibility to landslides? What is the relative importance of magma supply, upper plate structure, and crustal stress regime in controlling eruptive frequency? Are the size and location of earthquakes affected by structural boundaries, fluids, and fault geometry? How prevalent are cascading hazards over time? These and other geohazard questions can be addressed by studying behaviors across subduction zones or along subduction zones with contrasting segments. Ultimately, this understanding should motivate advances in predictive models. We invite observational, theoretical, laboratory, and modeling contributions that leverage the power of comparison across multiple subduction zones or along multiple subduction zone segments to develop new insights or test predictive models. Studies incorporating the SZ4D focus areas of Cascadia, Alaska and Chile are particularly welcome. 

• G - Geodesy
• NH - Natural Hazards
• S - Seismology
• V - Volcanology, Geochemistry and Petrology