Disturbance of trees by the 1857 Fort Tejon earthquake, California
Meisling, Kristian E.
Date of Issue1980
Trees may suffer damage during major earthquakes due to shaking or faulting of their substrate. Damage may result in temporarily asymmetric growth and/or reduction in width of annual growth rings. To determine whether trees contain useful records of prehistoric earthquakes in southern California, we cored eight conifers along the 1857 trace of the San Andreas fault near Wrightwood and Frazier Park, California. Annual ring widths were measured and plotted against the growth year determined by ring counting.We examined significant departures from normal growth trends and interpreted them in light of the 1857 earthquake and other possible environmental factors. Of eight trees sampled, five showed damage or growth anomalies attributablet o the 1857 event. One 120-year-old t ree straddling the fault is undamaged, suggesting no substantial slip since about 1870. To evaluate asymmetry, ratios of correlative rings widths from opposite sides of three seismically damaged trees were calculated and plotted against growth year. Two types of ratio anomalies can be recognized:(1) short-term,unilateral suppression of growth resulting from damage and (2) long-term,unilateral enhancement of growth attributable to tilt or changes in environmental factors. Further study of ring ratio anomalies may facilitate recognition of seismically damaged trees. Success in recognizing the 1857 event in five out of eight trees suggests that a larger suite of even older trees may contain a valuable 'dendroseismological' record of large prehistoric earthquakes in southern California.
DRNTU::Science::Geology::Volcanoes and earthquakes
Journal of geophysical research
© 1980 the American Geophysical Union. This paper was published in Journal of Geophysical Research and is made available as an electronic reprint (preprint) with permission of the American Geophysical Union. The paper can be found at the following official DOI: http://dx.doi.org/10.1029/JB085iB06p03225. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.