Figure Tags This file contains alternative-text for U.S. Geological Survey Open-File Report 2004-1204, The Cottage Lake aeromagnetic lineament: A possible onshore extension of the southern Whidbey Island Fault, Washington, by Blakely and others. These tags were originally placed in the PDF file, of2004-1204.pdf, but due to a failure of Acrobat 6, the tags came up under the wrong illustrations and this error was different on each download of the pdf. The best we can do is provide the text here. The cover figure shows a three-dimensional view of the residual magnetic anomaly over a digital terrain model. It also shows the location of lidar scarps and lineaments identified in this report. Figure 1 has two parts. Part A is a map showing the kinematic model of the Cascadia forearc. It points out that the Puget Lowland is squeezed beneath a northward migrating Oregon block and stationary North America. Part B shows a highly simplified geologic map of the Puget Lowland and surrounding regions. Important crustal faults are also shown. Figure 2 is a map showing evidence for the SWIF on Whidbey Island and surrounding waterways. It shows aeromagnetic anomalies and various strands of the SWIF interpreted by others on the basis of marine seismic-reflection data. It also shows the location of two marshes on Whidbey Island where evidence was found for a Holocene earthquake. Figure 3 is a map showing epicenters of crustal earthquakes occurring between 1971 and 2003. It also shows major regional faults interpreted from aeromagnetic anomalies. Figure 4 is a map showing the entire Puget Lowland aeromagnetic survey. It also indicates anomalies associated with major crustal faults: Devils Mountain, Utsalady, southern Whidbey Island, Seattle, Tacoma, and Olympia faults. Figure 5 shows aeromagnetic anomalies of the study area. The map also shows roads, towns, three strands of the SWIF (interpreted by others), the Cottage Lake aeromagnetic lineament, and the location of intense urbanization. Inset figures show llithologies interpreted by others within the Alderwood #1 and Socal-Schroeder #1 oil wells. Figure 6 is a demonstration of the "residual anomaly" technique. Map A shows a small aeromagnetic map of actual data from the Puget Lowland. The calculated anomaly of a hypothetical fault has been added to these data. Map B shows the data of Map A after application of the residual method. The anomaly due to the hypothetical fault is greatly enhanced in Map B. Figure 7 shows the aeromagnetic map of the study area after application of the residual technique. It also shows roads and towns and indicates the Cottage Lake aeromagnetic lineament. Figure 8 is a line drawing that illustrates a method to locate magnetic contacts from magnetic anomalies. The method involves three steps: transform the magnetic anomaly to pseudogravity, calculate the maximum horizontal gradient, and plot the location of all maxima on a map. Figure 9 is a map showing the residual magnetic anomaly of the study area and magnetic contacts calculated directly from the anomalies. The Cottage Lake aeromagnetic lineament is labeled. Figure 10 is a map showing residual magnetic anomalies, magnetic contacts calculated directly from the anomalies, and dotted and dashed lines indicating the most important northwest-trending aeromagnetic gradients. Dashed lines are high confidence; dotted lines are lower confidence. Figure 11 is a map showing magnetic anomalies after application of a matched filter. The filter was based on a fit to the power spectrum of the original data and designed to emphasize sources within a layer with top at 1245 m depth. It also shows interpreted magnetic lineaments. Figure 12 is a cartoon showing four ways to explain the aeromagnetic lineaments: Magnetic topography, fracture mineralization, faulted contact, and deposition contact. Figure 13 illustrates three maps of the study area. Map A shows digital topography, map B shows the altitude of the magnetic sensor above terrain, and map C shows the magnetic anomalies that would be expected if topography was uniformly magnetized. Each map also shows the interpreted magnetic lineaments. Figure 14 summarizes all of the observations of this report. It is a map of the study area showing interpreted magnetic lineaments, lidar scarps and lineaments, the location of the two deep oil wells, three strands of the SWIF interpreted by others, and the location of shallow boreholes along the wastwater conveyance system. Magnetic lineaments are labeled with letters and lidar features are labeled with numbers. The map also shows roads and towns. Figure 15A is a map of the Maltby-Woodinville area showing aeromagnetic anomalies superimposed on lidar topography. Scarps and topographic lineaments identified in this study are shown and numbered. Numbers refer to discussions in the text. The map also shows a series of lines identifying glacial flutes. Figure 15B is a map showing the northern limit of lidar coverage in the study area. Figure 16 is a map showing a lidar image of lineaments 1 through 3. Figure 17 shows a lidar image of features 4, 5, 6, and 8. Figure 18 shows a lidar image of feature 6. It also shows a topographic profile across the feature. Figure 19 shows a lidar image of lineament 7. Figure 20 shows a lidar image of and two topographic profiles across feature 8. Figure 21 shows a detailed lidar image of and topographic profile across feature 9. Figure 22 shows a detailed lidar image of and two topographic profiles across feature 10. Figure 23 shows a detailed lidar image of and topographic profiles across features 11 and 12. Figure 24 shows a detailed lidar image of and topographic profile across feature 13. Figure 25 shows a detailed lidar image of and topographic profile across feature 14. Figure 26 shows a detailed lidar image of and topographic profile across scarp 15. Figure 27 shows a detailed lidar image of and topographic profiles across features 16 and 17. Figure 28 shows a detailed lidar image of and two topographic profiles across scarp 18. Figure 29 shows a possible model for the Cottage Lake aeromagnetic lineament based on observed magnetic data. The model includes three magnetic units: very weakly magnetic Pleistocene deposits, a sequence of weakly magnetic sedimentary layers, and highly magnetic volcanic rocks. Lithologies of the Alderwood #1 and Socal-Schroeder #1 oil wells are shown for reference. The model includes a reverse fault cutting all three magnetic layers.