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Background lecture Various examples Web images Old business: Dating, discovering previously unknown earthquake on south PowerPoint Presentation
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Background lecture Various examples Web images Old business: Dating, discovering previously unknown earthquake on south - PowerPoint PPT Presentation

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Background lecture Various examples Web images Old business: Dating, discovering previously unknown earthquake on south
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  1. Dendrogeomorphology • Background lecture • Various examples • Web images • Old business: • Dating, discovering previously unknown earthquake on southern San Andreas • New business: • Current research on Parícutin eruption • Prep for Sunset Crater

  2. How Dendrogeomorphology • Any unusual change in ring growth • Decreased/increased width growth • Decreased/increased ring wood density

  3. How Dendrogeomorphology • Any unusual change in ring growth • Decreased/increased width growth • Decreased/increased ring wood density • Death/initiation date

  4. How Dendrogeomorphology • Any unusual change in ring growth • Decreased/increased width growth • Decreased/increased ring wood density • Death/initiation date • Reaction wood/abrasion scar

  5. Hebgen Lake, 1959

  6. Hebgen Lake, 1959

  7. How Dendrogeomorphology • Any unusual change in ring growth • Decreased/increased width growth • Decreased/increased ring wood density • Death/initiation date • Reaction wood/abrasion scar • Ring chemical changes • Nitrogen? • Strontium?

  8. What Dendrogeomorphology • Earthquakes: 1989 Loma Prieta

  9. What Dendrogeomorphology • Earthquakes • Volcanic eruptions

  10. What Dendrogeomorphology • Earthquakes • Volcanic eruptions • Other ground • Mud/debris flow, rockfall • Soil creep

  11. What Dendrogeomorphology • Earthquakes • Volcanic eruptions • Other ground • Mud/debris flow, rockfall • Soil creep • Water • Shoreline • Riverine

  12. What Dendrogeomorphology • Aeolian • Great L. dunes • Earthquakes • Volcanic eruptions • Other ground • Mud/debris flow, rockfall • Soil creep • Water • Shoreline • Riverine

  13. What Dendrogeomorphology • Aeolian • Great L. dunes • Earthquakes • Volcanic eruptions • Snow • Neo advances • Avalanches (Dexter) • Permafrost • Ice ramparts, jams • http://www.neatorama.com/2007/05/31/frozen-waves/ • Other ground • Mud/debris flow, rockfall • Soil creep • Water • Shoreline • Riverine

  14. What Dendrogeomorphology • Aeolian • Great L. dunes • Earthquakes • Volcanic eruptions • Snow • Neo advances • Avalanches (Dexter) • Permafrost • Ice ramparts, jams • http://www.neatorama.com/2007/05/31/frozen-waves/ • Other ground • Mud/debris flow, rockfall • Soil creep • Water • Shoreline • Riverine

  15. Why Dendrogeomorphology • Basic understanding of surficial processes • Dates, therefore frequency of events • Location, areal extent • Magnitude • Temporal-spatial coherence • E.g., volcanism related to seismicity? • Medicine Lake Highlands

  16. Why Dendrogeomorphology • Basic understanding of surficial processes • Dates, therefore frequency of events • Location • Magnitude • Temporal-spatial coherence • E.g., volcanism related to seismicity? • Medicine Lake Highlands • Future prediction not a goal so much

  17. Dendrogeomorphology Fundamentals • Uniformitarianism • Events affect trees similarly • Absolute conditions need not be similar • Limiting factors • Events change what limits tree growth • Site selection • Certainly not random • Carefully considered

  18. Dendrogeomorphology Fundamentals • Crossdating • Annual precision a strength of dendro • Getting “close” could be misleading • Sensitivity • Enough to facilitate crossdating • Not too much, mimic geomorphic signal • Replication • How many trees with geomorphic signal?

  19. Dendrogeomorphology Fundamentals • Control (expectation) • Growth prior to event • Growth of other trees after event • Departure from expectation • Also caused by climate, ecological events • Mapping often critical • Calibration to known event would be nice • Vanishing evidence

  20. DendrogeomorphologyQuadruple Junction • Geomorphic process, frequent and recent • Must damage trees without destroying evidence • Must be old trees, with crossdating • Compelling hazard to humans

  21. Dendroseismology:Southern California • Recent event (1857), previous event thought to be within 200 years • Living trees show 1857 event • Long-lived pines and firs • Millions of people living nearby, some right on the San Andreas

  22. Pool Tree • Huge Jeffrey • No top • Sag pond pool

  23. Lone Pine Canyon • Huge Jeffrey • No top • Right on fault

  24. All Trees • Control chronology robust • 1812 & 1857 drought years? • Nine event trees • Pines, firs • Confirm 1857, show 1812 • Span 12 km of fault

  25. San JuanCapistrano • 60 km south of Wrightwood • Big earthquake in 1812, Dec. 8.

  26. Interpretation • Short segment ruptured, but longer than our trees • The word “irregular” made it in title • 1812 45 yrs • 1857 146 yrs • 2003

  27. Another Interpretation • Seismic ruptures displace stress, rather than eliminate it (SciAm, Jan. 2003) • Stress displaced to the north? • 1812 southern California 45 yrs • 1857 central California 49 yrs • 1906 San Francisco • When will south start again?

  28. Dendrovolcanism:Sunset Crater • Last event not very recent (AD 1064?) • Trees from archeo collections show that event • Crossdating legendary • Sinaguans lived nearby • Calibration from Parícutin 1940s?

  29. Questions About Sunset • Nature of association of event trees with eruption? • Eruption perhaps a lengthy event? • Did ash truly improve environmental conditions for Sinagua? • “Blank Sand,” by Colton?

  30. Parícutin, Mexico • Cinder cone, similar to Sunset • Well known modern event • 1940s-50s eruption • Lava, ash fall well-mapped • Forested area, then and now • Perhaps could serve as a calibration for Sunset

  31. Parícutin • Big, young pines • Most start in 1960s • A few start in 1930s • Some old stumps • Dating not great, but passable • Measure widths and elements • S, P

  32. Interpretation (so far) • Clear visible effects on this tree • P and Ca response might be indirect  soil pH changes • Either way, a useful chemical variable • Will this show up in Sunset Crater archeo wood collection? • Could refine start date of eruption • Could better define length of eruption

  33. Dendovolvanics Mount St. Helens • A virtual dendrogeomorph playground • Recent eruptions • Lots of old trees • Lots of people

  34. 1842 1843 1845