全部书籍

1 Primary & Middle School Mathematics1–9 年级在线 2 High School Mathematics10–12 年级在线 3 University Mathematics — Year 1本科一年级在线 4 University Mathematics — Year 2本科二年级在线 5 University Mathematics — Year 3本科三年级在线

1 Primary & Middle School Physics1–9 年级在线 2 High School Physics10–12 年级在线 3 University Physics — Year 1本科一年级在线 4 University Physics — Year 2本科二年级在线 5 University Physics — Year 3本科三年级在线

1 School Chemistry — Grades 1 to 121–12 年级在线 2 University Chemistry — Year 1本科一年级在线 3 University Chemistry — Year 2本科二年级在线 4 University Chemistry — Year 3本科三年级在线

1 Primary & Middle School Biology1–9 年级在线 2 High School Biology10–12 年级在线 3 University Biology — Year 1本科一年级在线 4 University Biology — Year 2本科二年级在线 5 University Biology — Year 3本科三年级在线

1 Primary & Middle School Earth and Space Sciences1–9 年级在线 2 High School Earth and Space Sciences10–12 年级在线 3 University Earth and Space Sciences — Year 1本科一年级在线 4 University Earth and Space Sciences — Year 2本科二年级在线 5 University Earth and Space Sciences — Year 3本科三年级在线

1 Markets I: The Ecosystem and Exchange-Traded Markets市场在线 2 Markets II: Rates, FX and Credit市场在线 3 Markets III: Commodities, Energy and Crypto市场在线 4 Quantitative Methods方法在线 5 Derivatives and Volatility衍生品在线 6 Rates, Credit, XVA and Risk利率、信用与风险在线 7 Research Craft: Predictors, Backtests, Measurement, Portfolios研究在线 8 Strategies I: Equities and Futures策略在线 9 Strategies II: Volatility, Relative Value, Macro and the Bank Desks策略在线 10 Microstructure and Execution交易执行在线 11 Market Making and High-Frequency Trading做市在线 12 Machine Learning for Markets机器学习在线 13 Low-Latency Software技术在线 14 Networks, Hardware and Trading Infrastructure技术在线 15 Research, Data and Risk Platforms技术在线 16 The Desk and the Firm公司运营在线 17 The Industry: Firms, Roles and Careers职业发展在线 18 Interviews I: Maths, Probability and Speed职业发展在线 19 Interviews II: Markets, Trading Games and the Final Round职业发展在线 20 Interviews III: Code职业发展在线

全部游戏 Math Fuse Word Reactor Atlas Dash

应用关于

Coach

English Français Español Nederlands Português हिन्दी العربية Bahasa Indonesia 简体中文 বাংলা

登录开始阅读

书籍暂未推出简体中文版——当前显示英文版。

Earth and Space Sciences · 术语表

什么是 Travel-time table？

Definition 1.5 University Earth and Space Sciences — Year 3 · 第 1 章 — Seismology and Earth Imaging

A travel-time table gives, for each seismic phase (P, S, PKP, PcP, …) and each source depth, the travel time as a function of epicentral distance, computed from a spherically symmetric reference model whose speeds were themselves adjusted to fit the times of a large set of well-located earthquakes. Its differences from an observed arrival are the starting point of earthquake location and of tomography.

Travel times of P, S and the core phases from a surface source, computed through PREM by summing the integrals of over 2-km shells. The P curve ends at 98.5; its slope, the ray parameter, decreases with distance. Below 40 it has several overlapping branches (triplications): rays turning in the weak gradient between the Moho and 220\, km travel far, out to about 39, before the rays turned back at the discontinuities of the model, at 220, 400 and 670\, km, take over; the first arrival is always the lowest branch. The PKP curve folds back at the caustic B, at 143.8, and its short branch also includes the rays turned back at the inner-core boundary. The S curve (rays turning in the mantle; the S waves reflected off the core are left out) ends near 102: S does not cross the liquid outer core. — Travel times of P, S and the core phases from a surface source, computed through PREM by summing the integrals of Proposition 1.4 over 2-km shells. The P curve ends at $98.5{}^{\circ}$ ; its slope, the ray parameter, decreases with distance. Below $40{}^{\circ}$ it has several overlapping branches (triplications): rays turning in the weak gradient between the Moho and $220\,\mathrm{km}$ travel far, out to about $39{}^{\circ}$ , before the rays turned back at the discontinuities of the model, at 220, 400 and $670\,\mathrm{km}$ , take over; the first arrival is always the lowest branch. The PKP curve folds back at the caustic B, at $143.8{}^{\circ}$ , and its short branch also includes the rays turned back at the inner-core boundary. The S curve (rays turning in the mantle; the S waves reflected off the core are left out) ends near $102{}^{\circ}$ : S does not cross the liquid outer core.

在原文中阅读 →