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The deep critical zone (CZ) has long been recognized for its importance in influencing shallow landslides but was not considered feasible to include in slope stability models at the watershed scale. Here, we demonstrate that simple approximations of the CZ in a fully coupled hydrologic and soil slope stability model can effectively capture the location, timing, and likely size of shallow landslides. To achieve this, we use coupled, process-based models that incorporate the effects of 1) deep CZ structures, 2) three-dimensional transient hydrology, and 3) multidimensional slope stability, calibrated with data from an intensively monitored field site. Our results show that the hydrologically active deep CZ guides groundwater flow, influencing where it drains from or exfiltrates to the soil mantle and producing distinct patterns of soil saturation and seepage forces at the soil–bedrock boundary. A deep conductive, weathered bedrock drains the soil mantle, reducing the likelihood of destabilizing pore pressures, while the downslope thinning of the CZ forces groundwater to the surface. This pattern creates localized instability and a tendency for similar-sized landslides across the landscape. In contrast, the absence of conductive weathered bedrock results in more widespread destabilizing pore pressures, leading to larger landslides and the likelihood of landslides earlier in a storm than in landscapes underlain by a deep CZ. Our findings suggest that first-order variations of deep CZs can provide physical explanations for variations observed in the susceptibility, magnitude, and timing of shallow landslides, and that CZ structure may be inferred from patterns and timing of landsliding. 

Indigenous knowledge can record scientific observations of specific “places” that may be difficult to preserve in the geological record. Such a place in “place-based” science highlights issues local to a learner with regard to engaging audiences on the scientific problems relevant to their communities. Here, we focus on a popular seafaring repertoire of Indigenous Ryukyuan classical music, called Nubui Kuduchi and Kudai Kuduchi, to examine place-based observations of 18th-century climate and geology in the Ryukyu Islands (21st-century Okinawa Prefecture, Japan). By comparing the environmental conditions recorded in these songs with those of 20th- and 21st-century studies, we find that surface winds, ocean currents, typhoons, and volcanism from lyrics parallel their respective observations in the scientific record. This novel perspective of art and science highlights the relevance of Ryukyuan classical music in teaching contemporary issues such as climate change and natural hazards. Thus, Ryukyuan Indigenous knowledge can play an innovative role in science engagement for 21st-century Okinawans in Okinawa Prefecture and for their diasporic kinsfolk worldwide. 

{"Abstract":["Drone image-derived digital elevation model at 'flight of terraces' site in "Microcontinent Breakup and Links to Possible Plate Boundary Reorganization in the Northern Gulf of California, México" created with Agisoft Photoscan software. WGS1984 UTM Zone 12N."]} 

{"Abstract":["Drone image-derived digital elevation model at 'southern terraces' site in "Microcontinent Breakup and Links to Possible Plate Boundary Reorganization in the Northern Gulf of California, México" created with Agisoft Photoscan software. WGS1984 UTM Zone 12N."]} 

{"Abstract":["Drone image-derived digital elevation model at 'incised terrace' site in "Microcontinent Breakup and Links to Possible Plate Boundary Reorganization in the Northern Gulf of California, México" created with Agisoft Photoscan software. WGS1984 UTM Zone 12N."]} 

{"Abstract":["This is the 3-m resolution digital elevation model from "Microcontinent Breakup and Links to Possible Plate Boundary Reorganization in the Northern Gulf of California, México". Digital elevation was constructed from two 0.5-m resolution Pleiades satellite images (product type: 50cm Panchromatic + 2m (4-Band) Multispectral Bundle) using the NASA Ames Stereo Pipeline software. WGS1984 UTM Zone 12N."]} 

{"Abstract":["Drone image-derived digital elevation model at sag pond site in "Microcontinent Breakup and Links to Possible Plate Boundary Reorganization in the Northern Gulf of California, México" created with Agisoft Photoscan software. WGS1984 UTM Zone 12N."]} 

{"Abstract":["Dosimetry data, equivalent doses, and single grain post-infrared infrared stimulated luminescence (p-IR IRSL) ages from "Microcontinent Breakup and Links to Possible Plate Boundary Reorganization in the Northern Gulf of California, México". Also shown in Table S2 of publication's supplementary file."]}