Very Precise Dating of Prehistoric Earthquakes in Southern California Using Tree-ring Analysis

利用树木年轮分析对南加州史前地震进行非常精确的测年

• 批准号: 8707967
• 负责人: Gordon Jacoby
• 金额: --
• 依托单位: Columbia University Lamont Doherty Earth Observatory
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-01 至 1988-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8707967&HistoricalAwards=false
• 关键词: Very; Precise; Dating; Prehistoric; Earthquakes

It is proposed herein to continue sampling along the San Andreas fault in order to find more old-aged trees that have been disturbed by earthquakes. These disturbed trees can provide information about timing and extent of prehistoric earthquake events as their records of annual growth rings are dated and deciphered. Previous tree-ring ssampling and new samples from the first supported part of this project confirm the effects of the 1857 earthquake in certain trees in southern California. Samples along a 10 km length of the San Andreas fault just northwest of Cajon Pass show evidence of strong disturbance between the growing seasons of 1812 and 1813. A reported great earthquake in 1812 encourages the interpretation that tree-ring data can define the location of this earthquake, which is known in time but not in space. Further sampling and study will ensue in this area, because the interval of only 44 years, between 1812 (December) and 1857 (January), is much shorter than previous estimated recurrence intervals along this segment. Precise delineation of extent of rupture in late 1812 will be the primary focus of this research. Studies will also continue on samples from other segments of the San Andreas fault. Within constraints of time, efforts will continue in northern California. The concentration there will be on the extent of the 1838 event in the Bay Area region.

建议继续沿圣安德烈亚斯断层沿着取样，以寻找更多受地震扰动的古树。这些受干扰的树木可以提供有关史前地震事件的时间和程度的信息，因为它们的年轮记录可以被确定和破译。以前的树木年轮取样和来自该项目第一个支持部分的新样本证实了1857年地震对加州南部某些树木的影响。沿着卡洪山口西北部圣安德烈亚斯断层沿着10公里长的样本显示出1812年和1813年生长季节之间强烈干扰的证据。1812年的一次大地震的报道鼓励了这样的解释，即树木年轮数据可以确定这次地震的位置，这在时间上是已知的，但在空间上是未知的。在这一地区将继续进行进一步的取样和研究，因为从1812年（12月）到1857年（1月）的44年间隔比以前估计的沿这一段的重现间隔沿着要短得多。1812年后期破裂范围的精确描绘将是本研究的主要重点。研究还将继续对圣安德烈亚斯断层其他部分的样本进行研究。在有限的时间内，将继续在北方加州开展工作。那里的重点将是1838年事件在湾区地区的程度。