...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Volcanology and Geothermal Research >Are volcanic seismic b-values high, and if so when?
【24h】

Are volcanic seismic b-values high, and if so when?

机译：火山地震b值高吗？

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The Gutenberg-Richter exponent b is a measure of the relative proportion of large and small earthquakes. It is commonly used to infer material properties such as heterogeneity, or mechanical properties such as the state of stress from earthquake populations. It is 'well known' that the b-value tends to be high or very high for volcanic earthquake populations relative to b = 1 for those of tectonic earthquakes, and that b varies significantly with time during periods of unrest. We first review the supporting evidence from 34 case studies, and identify weaknesses in this argument due predominantly to small sample size, the narrow bandwidth of magnitude scales available, variability in the methods used to assess the minimum or cutoff magnitude M-c, and to infer b. Informed by this, we use synthetic realisations to quantify the effect of choice of the cutoff magnitude on maximum likelihood estimates of b, and suggest a new work flow for this choice. We present the first quantitative estimate of the error in b introduced by uncertainties in estimating M-c, as a function of the number of events and the b-value itself. This error can significantly exceed the commonly-quoted statistical error in the estimated b-value, especially for the case that the underlying b-value is high. We apply the new methods to data sets from recent periods of unrest in El Hierro and Mount Etna. For El Hierro we confirm significantly high b-values of 1.5-2.5 prior to the 10 October 2011 eruption. For Mount Etna the b-values are indistinguishable from b = 1 within error, except during the flank eruptions at Mount Etna in 2001-2003, when 1.5 < b < 2.0. For the time period analysed, they are rarely lower than b = 1. Our results confirm that these volcano-tectonic earthquake populations can have systematically high b-values, especially when associated with eruptions. At other times they can be indistinguishable from those of tectonic earthquakes within the total error. The results have significant implications for operational forecasting informed by b-value variability, in particular in assessing the significance of b-value variations identified by sample sizes with fewer than 200 events above the completeness threshold. (C) 2015 Elsevier B.V. All rights reserved.
机译：古腾堡-里希特指数b是大地震和小地震相对比例的度量。它通常用于推断材料属性（例如非均质性）或机械属性（例如来自地震种群的应力状态）。众所周知，火山地震人口的b值相对于构造地震的b值倾向于高或非常高，并且在动荡时期b随时间变化很大。我们首先回顾来自34个案例研究的支持证据，并找出该论点的弱点，这些弱点主要是由于样本量小，可用的量级尺度的带宽窄，用于评估最小或截断值Mc的方法的可变性以及推断b 。以此为依据，我们使用综合实现方法来量化临界值选择对b的最大似然估计的影响，并为该选择提出新的工作流程。我们提出了由不确定性在估计M-c中引入的b误差的第一个定量估计，它是事件数量和b值本身的函数。该误差可能会大大超过估算的b值中常用的统计误差，尤其是对于基础b值较高的情况。我们将新方法应用于最近在El Hierro和Mount Etna发生动乱的数据集。对于El Hierro，我们确认在2011年10月10日喷发之前b值显着较高，为1.5-2.5。对于埃特纳火山，在2001年至2003年埃特纳火山的侧翼爆发时，当1.5

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号