Station). Just four miles (6 km) south the city of Oak Harbor straddles several stands of the Utsalady Point Fault (UPF) as they head roughly east-southeast towards Utsalady Point at the north end of Camano Island. And in between these two the Strawberry Point Fault (SPF) skirts the south side of Ault Field, splits into various strands that bracket Strawberry Point, and then disappear (possibly ending) under the delta of the Skagit River. Both the SPF and UPF are said to be oblique-slip transpressional; that is, the faults show both horizontal and vertical slip as the crustal blocks are pressed together. These faults also form the north and south boundaries of uplifted pre-Tertiary rock, suggesting that the faults come together at a lower level, much like one model of the Seattle and Tacoma faults, but at a smaller scale. Marine seismic reflection surveys on either side of Whidbey Island extend the known length of these faults to at least 26 and 28 km (about 15 miles). The true length of the UPF is likely twice as long, as it forms the southern margin of an aeromagnetic high that extends another 25 km to the southeast. Trenching on the UPF (at a scarp identified by LIDAR) shows at least one and probably two Holocene earthquakes of magnitude 6.7 or more, the most recent one between AD 1550 to 1850, and possibly triggered by the 1700 Cascadia earthquake. These earthquakes probably caused tsunamis, and several nearby locations have evidence of tsunamis not correlated with other known quakes. While there is a bit of uplifted pre-Tertiary rock between the SPF and UPF, this does not truly fit the uplift and basin pattern described above because of the small scale (2 km wide rather than around 20), and because the uplift here is entirely like a wedge being popped out between two nearly vertical faults, rather than being forced over a ramp such as is involved with the Seattle and Tacoma faults. Nor does this uplift delineate any significant basin between it and the Devils Mountain Fault. On the basis of marine seismic reflection surveying in the Strait of Juan de Fuca it has been suggested that the DMF, SPF, and UPF are structurally connected (at least in the segment crossing Whidbey Island). USGS QFFDB Fault #571, Strawberry Point Fault USGS QFFDB Fault #573, Utsalady Point Fault Southern Whidbey Island Fault The Southern Whidbey