The 2026-04-13 M5.7 Lake Lahontan, NV Earthquake: coseismic damage, aftershocks and afterslip

Christie D. Rowe, Hannah Martin, Maggie Duncan, Daniel T. Trugman, Rich D. Koehler, Harriet Z. Yin, Katherine A. Guns, Catherine E. Hanagan, Ian Pierce, William C. Hammond, & Evan Hartshorn

Submitted August 30, 2026, SCEC Contribution #15594, 2026 SCEC Annual Meeting Poster #109

The Lake Lahontan M5.7 earthquake occurred on April 13, 2026, in the Dead Camel Mountains between Fallon and Silver Springs, NV. Historic adobe buildings were damaged, but otherwise shaking caused only minor, mostly non-structural damage. The rupture plane was oriented 61/80°S with nearly pure sinistral movement (rake = 5°). The hypocenter was ~5 km and resulted in surface rupture and cracking in the Dead Camel Mountains, and deformation along the rupture trace on Alkali Flats, an adjacent saline clay playa. We mapped surface fractures with drone imagery. Cracks follow the rupture trace trending ~60°, as well as ~20°-trending sinistral-opening mode crack sets which may form a horsetail fracture array. These are best preserved in ~14 ka Lake Lahontan highstand shoreline silts but not preserved in the rubbly volcanic exposures. Along strike, an area of playa surface about 1 km across translated slightly, and its perimeter is marked by clusters of low mounds of dried mud, some with summit depressions, which we interpret as vent structures formed by liquefaction and expulsion of muddy brine during the earthquake.

Four days after the mainshock, aftershocks started on a parallel structure, offset ~1 km to the south-southwest of the western end of the mainshock plane. Around the same time, Sentinel-1 interferograms identified aseismic slip along the mainshock plane, and extending along strike to the southwest, not co-located with the second aftershock plane. No surface deformation features were discovered in the afterslip area, but geodetic measurements at a nearby EarthScope Network of the Americas station showed significant postseismic displacement consistent with afterslip occurred for several weeks.

The Lake Lahontan earthquake produced ~ 3x more detectable aftershocks than a similar M5.7 sinistral earthquake that occurred in December 2024, 15 km to the south, near Parker Butte in the northern Mason Valley. In the Parker Butte event, dextral aseismic triggered slip occurred on an orthogonal structure (both the main and orthogonal structures were previously unmapped, but geomorphic and field evidence for both faults was discovered after the earthquakes). Together, these events demonstrate that the Walker Lane fault maps are incomplete, that faults with no geomorphic expression are still capable of producing damaging earthquakes, and show for the first time that aseismic afterslip may contribute to the overall deformation field in the Walker Lane.

Key Words
afterslip, aftershocks, surface rupture, perishable data, rapid response, shallow deformation, geomorphic expression, co-seismic damage

Citation
Rowe, C. D., Martin, H., Duncan, M., Trugman, D. T., Koehler, R. D., Yin, H. Z., Guns, K. A., Hanagan, C. E., Pierce, I., Hammond, W. C., & Hartshorn, E. (2026, 08). The 2026-04-13 M5.7 Lake Lahontan, NV Earthquake: coseismic damage, aftershocks and afterslip. Poster Presentation at 2026 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Geology