The June 24, 2026 M5.6 Redwood Valley, CA earthquake and creep on the Maacama fault

Gareth J. Funning

Submitted August 30, 2026, SCEC Contribution #15598, 2026 SCEC Annual Meeting Poster #TBD

At 8:10 am local time on June 24th, 2026, a M5.6 event shook Redwood Valley in northern California, causing minor damage, power outages and minor injuries in surrounding communities. The epicenter of the event lies close to the trace of the Maacama fault, but it was not immediately clear if the earthquake was on the main Maacama fault or on a secondary fault. In addition, both InSAR and repeating earthquake evidence suggests that the shallow part (upper 6 km) of the Maacama fault in the area is creeping, raising a further question as to the relationship between seismic and aseismic slip in the area.

To investigate these questions, I examine InSAR data from both Sentinel-1 and NISAR, covering the epicenter of the earthquake. Both ascending and descending Sentinel-1 coseismic interferograms are dominated by tropospheric noise, but through making short sequential interferogram stacks it is possible to identify consistent signals – a pair of deformation lobes showing range decrease (uplift) to the NW and range increase (subsidence) to the SE in both, located a few km to the east of the Maacama fault trace. A similar feature in the same place is also visible in an ionosphere-corrected NISAR interferogram spanning the earthquake. Preliminary modeling suggests that this pattern is consistent with strike-slip motion on a fault with similar strike to the Maacama fault dipping at ~50° to the NE based on the NCEDC moment tensor solution, with the top edge of the source at ~6 km depth.

Such a shallow dip is unusual for a major strike-slip fault, but consistent with the seismicity associated with the Maacama fault, which forms a NE-dipping trend at that latitude, and contains multiple candidate repeating earthquake families which are likely markers of fault creep at depth. I plan more detailed dislocation modeling of the InSAR displacements to further investigate the spatial relationship between repeating earthquakes, creep and this potential earthquake asperity.

Citation
Funning, G. J. (2026, 08). The June 24, 2026 M5.6 Redwood Valley, CA earthquake and creep on the Maacama fault. Poster Presentation at 2026 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy