NNE of Carnation, location of the 1965 Duvall earthquake. Between the Cherry Creek and parallel Tokul Creek faults is a contact between formations of the Western Melange Belt. The zone between these two lines, reflecting changes in regional structure, seismicity, fault orientation, and possibly the underlying lithospheric structure, appears to be a major structural boundary in the Puget Lowland. Also intersecting at Mount St. Helens is a NE (045°) trending line (red) of Pleistocene (about 4 Ma) plug domes and a topographic lineament (followed in part by Highway 12). This line is the southernmost of a band of NE trending faults and topographical lineaments that extend from the Oregon coast into the North Cascades. A similar line aligns with the termination of the WRZ, SHZ, and Gales Creek Fault Zone (northwest of Portland), with faulting along the upper Nehalem River on the Oregon coast, and a topographical contrast at the coast (between Neahkahnie Mountain and the lower Nehalem River valley) distinct enough to be seen on the seismicity map above (due west of Portland). Other similar lineaments (such as from Astoria to Glacier Peak) align with various topographical features and changes in fault orientation. These lineaments have been associated with possible zones of faulting in the crust and subducting plate. These features suggest that the southern Puget Lowland is influenced by the deep crust and even the subducting Juan de Fuca plate, but the details and implications are not yet known. Other faults Actual There are numerous other faults (or fault zones) in the Puget Lowland, and around its edges, sketchily studied and largely unnamed. These are usually fairly short, and not believed to be significantly seismogenic. However, most seismic activity is not associated with any known fault. Seismicity sometimes occurs in zones, such as has been observed under Mercer Island, or from downtown Seattle towards Kirkland but whether particular zones reflect undiscovered faults, or might be the source of damaging earthquakes, is generally unknown. Ongoing mapping is revealing more faults. E.g., mapping along the Rattlesnake Mountain Fault Zone has revealed a complex network of active or potentially active faults across (and likely beyond) the lower Snoqualmie Valley, including the Cherry Creek Fault Zone, scene of the 1996 M 5.3 Duvall earthquake. The San Juan Island and Leach River faults crossing the southern end of Vancouver Island are significant and undoubtedly connected with the Darrington—Devils Mountain and Southern Whidbey Island