2. The MARGINS Program “To understand the complex interplay of processes that govern the evolution of continental margins”

3. MARGINS has four themes: Rupturing Continental Lithosphere, Seismogenic Zone, Subduction Factory, and SOURCE TO SINK

4. Writing Earth history with continental- margin sedimentary processes WRITING EARTH HISTORY WITH CONTINENTAL-MARGIN SEDIMENTARY PROCESSES

6. Jantang, Sumatra Courtesy of H. Higman

7. Photo: Brian Atwater Courtesy of Brian Atwater

8. 41 o 00’ 40 o 50’ 40 o 40’ 124 o 40’ 124 o 30’ 7 0 0 6 0 0 5 0 0 4 0 0 3 5 0 3 0 0 2 5 0 2 0 0 1 5 0 1 0 0 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 0 1 0 Eel River Drainage Basin ~9000 km 2 Study Area 0 m 350 1400 Elevation California Eel margin

9. Courtesy of Jeff Borgeld

10. Wheatcroft and Borgeld, 2000

11. Fingerprint of Flood Sedimentation on the Eel Shelf (Sommerfield et al., 1999)

12. Sommerfield et al., 2007

13. S 60  Location of observations in Eel Canyon

14. Eel Canyon Morphology Complex channel shape makes placement of sediment cores difficult

19. ( Mullenbach and Nittrouer, in 2004) Sedimentary fingerprints indicates that flood sediments are entering submarine canyon

20. Southeast Alaska Coast Sediment supplied from glacier-fed rivers Courtesy of John Jaeger

21. Surge events from Bering Glacier recorded on adjacent shelf Courtesy of John Jaeger

23. Courtesy of Peter Harris

26. Modern Coastal Rivers Courtesy of Bill Dietrich Obo

27. From Lui et al. (2003)

28. NORTHERN ADRIATIC SEA Po River ITALY CROATIA Ancona Promontory Gargano Peninsula Apennine Mountains Venice Lagoon

30.  abandonment of Po di Primaro  1152 AD a major natural avulsion  northward shifting of distributary channels  Venice Republic is threatened by the potential infilling of the lagoon  1604 AD digging of a diversionary canal (Taglio di porto Viro) The artificial form of the modern delta

31. NORTHERN ADRIATIC SEA Po River ITALY CROATIA Ancona Promontory Gargano Peninsula Apennine Mountains Venice Lagoon

32. History of Apennine sediment discharge Excess 210 Pb Activity (dpm/g) 0 50 100 150 200 250 1.010.0 Supported = 0.7 0.1 11.2 mm/y R 2 = 0.72 15.0 mm/y R 2 = 0.97 7.80 mm/y R 2 = 0.89 Tronto River 9.7 mm/y 3.2 mm/y Eel RiverSangro River 0 50 100 150 200 250 1.010.0 Excess 210 Pb Activity (dpm/g) 0.1 10.2 mm/y R 2 = 0.68 15.4 mm/y R 2 = 0.96 6.58 mm/y R 2 = 0.97 (KS02-30)(KS02-355) Dams reduce sediment accumulation in Adriatic Sea

33. Clearcutting increases sediment load Dams reduce sediment load DAMS WIN

34. Sediment source for southern WA coast beaches Dams placed on Columbia River during 20 th century likely trapped much sediment Greatest impact reached the coast in ~1980, after lower river was flushed

35. Ocean waves and currents transport sediment northward, distributing it along beach and continental shelf Coast of Washington State Southwest Washington Erosion Study

36. Changes in Wave Climate (Allan and Komar, 2001)

37. Coastal erosion has caused loss of structures and roads And has led to hardening of the shoreline in some places

38. Mississippi Delta Historically has provided coastal protection to New Orleans Bird-foot delta Sedimentation extends to shelf break

39. List of some things we did Dammed river – reduced sediment supply, 400 million t/y to 200 t/y Built artificial levees – reduced nourishment of flood plain Prevented lobe switching – reduced sediment supply to other parts of delta plain (30% to Atchafalaya) Constrained flow to modern delta – caused delta to build to shelf break, and lose sediment to continental slope Removed water and natural gas – accelerated consolidation of deltaic sediment and subsidence of land surface Dredged channels – created depressions that act as sediment traps and water conduits

40. Writing Earth history with continental- margin sedimentary processes IF WE DON’T LEARN FROM HISTORY, WE’RE DOOMED TO RELIVE IT

43. Trees are ripped out of hills to an elevation of >30 m by the tsunami in Sumatra (just south of Lho Nga) Courtesy of H. Higman

44. Tsunami transported bridge at Jantang, Aceh (Sumatra)

45. 2/27/99