当前位置: X-MOL 学术Pure Appl. Geophys. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Updates to the Regional Seismic Travel Time (RSTT) Model: 2. Path-dependent Travel-time Uncertainty
Pure and Applied Geophysics ( IF 1.9 ) Pub Date : 2021-01-25 , DOI: 10.1007/s00024-021-02657-7
Michael L. Begnaud , Dale N. Anderson , Stephen C. Myers , Brian Young , James R. Hipp , W. Scott Phillips

The regional seismic travel time (RSTT) model and software were developed to improve travel-time prediction accuracy by accounting for three-dimensional crust and upper mantle structure. Travel-time uncertainty estimates are used in the process of associating seismic phases to events and to accurately calculate location uncertainty bounds (i.e. event location error ellipses). We improve on the current distance-dependent uncertainty parameterization for RSTT using a random effects model to estimate slowness (inverse velocity) uncertainty as a mean squared error for each model parameter. The random effects model separates the error between observed slowness and model predicted slowness into bias and random components. The path-specific travel-time uncertainty is calculated by integrating these mean squared errors along a seismic-phase ray path. We demonstrate that event location error ellipses computed for a 90% coverage ellipse metric (used by the Comprehensive Nuclear-Test-Ban Treaty Organization International Data Centre (IDC)), and using the path-specific travel-time uncertainty approach, are more representative (median 82.5% ellipse percentage) of true location error than error ellipses computed using distance-dependent travel-time uncertainties (median 70.1%). We also demonstrate measurable improvement in location uncertainties using the RSTT method compared to the current station correction approach used at the IDC (median 74.3% coverage ellipse).

中文翻译:

区域地震走时 (RSTT) 模型更新:2. 路径相关走时不确定性

开发了区域地震走时(RSTT)模型和软件,通过考虑三维地壳和上地幔结构来提高走时预测精度。旅行时间不确定性估计用于将地震相位与事件相关联并准确计算位置不确定性界限(即事件位置误差椭圆)的过程。我们使用随机效应模型改进 RSTT 的当前依赖于距离的不确定性参数化,以将慢度(逆速度)不确定性估计为每个模型参数的均方误差。随机效应模型将观察到的慢度和模型预测的慢度之间的误差分为偏差和随机分量。通过沿地震相位射线路径对这些均方误差进行积分来计算路径特定的走时不确定性。我们证明,针对 90% 覆盖率椭圆度量(由全面禁止核试验条约组织国际数据中心 (IDC) 使用)计算的事件位置误差椭圆,以及使用特定路径的旅行时间不确定性方法,更具代表性(中位数 82.5% 的椭圆百分比)真实位置误差比使用与距离相关的旅行时间不确定性(中位数 70.1%)计算的误差椭圆高。我们还展示了使用 RSTT 方法与 IDC 使用的当前站校正方法(中位数为 74.3% 覆盖椭圆)相比在位置不确定性方面的可测量改进。并且使用特定路径的旅行时间不确定性方法,比使用依赖于距离的旅行时间不确定性(中值 70.1%)计算的误差椭圆更能代表真实位置误差(中值 82.5% 的椭圆百分比)。我们还展示了使用 RSTT 方法与 IDC 使用的当前站校正方法(中位数为 74.3% 覆盖椭圆)相比在位置不确定性方面的可测量改进。并且使用特定路径的旅行时间不确定性方法,比使用依赖于距离的旅行时间不确定性(中值 70.1%)计算的误差椭圆更能代表真实位置误差(中值 82.5% 的椭圆百分比)。我们还展示了使用 RSTT 方法与 IDC 使用的当前站校正方法(中位数为 74.3% 覆盖椭圆)相比在位置不确定性方面的可测量改进。
更新日期:2021-01-25
down
wechat
bug