# 第四册 Lesson 42 Recording an earthquake 记录地震

## 一、课文原文

An earthquake comes like a thief in the night, without warning. It was necessary, therefore, to invent instruments that neither slumbered nor slept. Some devices were quite simple. One, for instance, consisted of rods of various lengths and thicknesses which would stand up on end like ninepins. When a shock came, it shook the rigid table upon which these stood. If it were gentle, only the more unstable rods fell. If it were severe, they all fell. Thus the rods, by falling, and by the direction in which they fell, recorded for the slumbering scientist the strength of a shock that was too weak to waken him, and the direction from which it came.

But instruments far more delicate than that were needed if any really serious advance was to be made. The ideal to be aimed at was to devise an instrument that could record with a pen on paper, the movements of the ground or of the table as the quake passed by. While I write my pen moves, but the paper keeps still. With practice, no doubt, I could in time learn to write by holding the pen still while the paper moved. That sounds a silly suggestion, but that was precisely the idea adopted in some of the early instruments (seismometers) for recording earthquake waves. But when table, penholder and paper are all moving, how is it possible to write legibly? The key to a solution of that problem lay in an everyday observation. Why does a person standing in a bus or train tend to fall when a sudden start is made? It is because his feet move on, but his head stays still. A simple experiment will help us a little further. Tie a heavy weight at the end of a long piece of string. With the hand held high in the air, hold the string so that the weight nearly touches the ground. Now move the hand to and fro and around but not up and down. It will be found that the weight moves but slightly or not at all. Imagine a pen attached to the weight in such a way that its point rests upon a piece of paper on the floor. Imagine an earthquake shock shaking the floor, the paper, you and your hand. In the midst of all this movement, the weight and the pen would be still. But as the paper moved from side to side under the pen point, its movement would be recorded in ink upon its surface. It was upon this principle that the first instruments were made, but the paper was wrapped round a drum which rotated slowly. As long as all was still, the pen drew a straight line, but while the drum was being shaken, the line that the pen was drawing wriggled from side to side. The apparatus thus described, however, records only the horizontal component of the wave movement, which is, in fact, much more complicated. If we could actually see the path described by a particle, such as a sand grain in the rock, it would be more like that of a bluebottle buzzing round the room; it would be up and down, to and fro and from side to side. Instruments have been devised and can be so placed that all three elements can be recorded in different graphs.

When the instrument is situated at more than 700 miles from the earthquake centre, the graphic record shows three waves arriving one after the other at short intervals. The first records the arrival of longitudinal vibrations. The second marks the arrival of transverse vibrations which travel more slowly and arrive several minutes after the first. These two have travelled through the earth. It was from the study of these that so much was learnt about the interior of the earth. The third, or main wave, is the slowest and has travelled round the earth through the surface rocks.

— H.H. SWINNERTON, *The Earth beneath Us*

## 二、重点词汇详解

| 单词 | 音标 | 词性 | 释义 | 用法说明 |
|------|------|------|------|----------|
| slumber | /ˈslʌmbə/ | v. | 睡眠 | neither slumbered nor slept 既不瞌睡也不睡眠 |
| rod | /rɒd/ | n. | 杆，棒 | rods of various lengths 不同长度的杆 |
| ninepin | /ˈnaɪnpɪn/ | n. | 九柱戏的瓶 | stand up on end like ninepins 像九柱戏瓶一样竖着 |
| rigid | /ˈrɪdʒɪd/ | adj. | 坚硬的，刚性的 | rigid table 坚硬的桌子 |
| seismometer | /saɪzˈmɒmɪtə/ | n. | 地震仪 | seismic adj. 地震的 |
| legibly | /ˈledʒəbli/ | adv. | 清晰地，可辨认地 | write legibly 写得清晰 |
| wriggle | /ˈrɪɡl/ | v. | 蠕动，扭动 | wriggled from side to side 左右扭动 |
| component | /kəmˈpəʊnənt/ | n. | 分量，成分 | horizontal component 水平分量 |
| bluebottle | /ˈbluːbɒtl/ | n. | 绿头苍蝇 | buzzing round the room 在房间里嗡嗡飞 |
| longitudinal | /ˌlɒndʒɪˈtjuːdɪnl/ | adj. | 纵向的 | longitudinal vibrations 纵波 |
| transverse | /ˈtrænzvɜːs/ | adj. | 横向的 | transverse vibrations 横波 |
| vibration | /vaɪˈbreɪʃn/ | n. | 振动 | earthquake vibrations 地震振动 |

**固定搭配：**
- **like a thief in the night**：像夜间的小偷一样（悄无声息）
- **to and fro**：来回
- **from side to side**：左右
- **one after the other**：一个接一个

## 三、语法知识点

### 1. neither...nor... 双重否定

> instruments that **neither** slumbered **nor** slept

既不……也不……，双重否定加强语气。

### 2. It was...that... 强调句

> **It was upon this principle that** the first instruments were made

强调方式状语 upon this principle。

### 3. 虚拟语气

> **If** we **could** actually see the path described by a particle...**it would be** more like that of a bluebottle

与现在事实相反的虚拟条件句。

### 4. It was from...that... 强调句

> **It was from the study of these that** so much was learnt about the interior of the earth

强调来源 from the study of these。

## 四、重点句型分析

### 句型1：类比说明

> An earthquake comes **like a thief in the night**, without warning

- 明喻：地震→夜间小偷
- 特点：无声无息、不可预测

### 句型2：实验推理

> Tie a heavy weight...hold the string...move the hand...It will be found that the weight moves but slightly or not at all

- 用日常实验说明惯性原理
- 步骤式描述，逻辑清晰

### 句型3：波形描述

> The first records the arrival of longitudinal vibrations. The second marks the arrival of transverse vibrations...The third, or main wave, is the slowest

- 三种波按到达顺序排列
- 由快到慢，由内到外

## 五、课文翻译

地震像夜间的小偷一样悄无声息地来临，毫无征兆。因此，有必要发明既不打瞌睡也不睡觉的仪器。有些装置相当简单。例如，有一种由不同长度和粗细的杆组成，像九柱戏的瓶子一样竖立着。地震来时，震动了这些杆站立的坚硬桌面。如果震动轻微，只有较不稳定的杆倒下。如果震动剧烈，全部倒下。因此，这些杆通过倒下以及倒下的方向，为沉睡的科学家记录了太弱而无法唤醒他的震动强度和来源方向。

但如果要取得真正重大的进展，就需要远比那更精密的仪器。理想的目标是设计一种能用笔在纸上记录地震经过时地面或桌面运动的仪器。我写字时笔移动，但纸保持不动。经过练习，毫无疑问我最终能学会在纸移动时保持笔不动来写字。这听起来像个可笑的建议，但这正是一些早期记录地震波的仪器（地震仪）所采用的想法。但当桌子、笔架和纸都在移动时，怎么可能写得清楚呢？解决这个问题的关键在于一个日常观察。为什么站在公共汽车或火车上的人在突然启动时容易摔倒？因为他的脚移动了，但头保持不动。一个简单的实验能帮助我们进一步理解。在一根长绳的末端系一个重物。手高高举在空中，握住绳子使重物几乎碰到地面。现在让手来回和旋转移动，但不要上下移动。你会发现重物几乎不动或完全不动。想象一支笔以某种方式固定在重物上，笔尖接触地板上的一张纸。想象地震震动地板、纸、你和你的手。在所有这些运动中，重物和笔是静止的。但当纸在笔尖下左右移动时，它的运动就会被墨水记录在表面上。第一批仪器就是根据这个原理制造的，但纸包裹在一个缓慢旋转的鼓上。只要一切静止，笔画出一条直线，但当鼓被摇动时，笔画出的线就左右扭动。然而，上述装置只记录了波浪运动的水平分量，实际上波浪运动要复杂得多。如果我们能实际看到一颗粒子（如岩石中的沙粒）所描绘的路径，它会更像一只绿头苍蝇在房间里嗡嗡飞；有上下、来回和左右。已经设计出的仪器可以这样放置，使三个分量都能在不同的图表上记录下来。

当仪器位于距震中700英里以上时，图形记录显示三个波以短间隔一个接一个到达。第一个记录纵波的到达。第二个标记横波的到达，横波传播较慢，在第一个之后几分钟到达。这两个波穿过地球内部传播。正是通过对这些波的研究，人们才了解了如此多关于地球内部的知识。第三个波即主波，最慢，沿地球表面岩石传播。

## 六、语言点精讲

### 1. 写作手法：从简单到复杂

- 先介绍简单装置（竖杆）
- 再介绍精密仪器（地震仪）
- 最后说明波的分类

### 2. 逻辑结构

| 段落 | 主题 | 论证方式 |
|------|------|----------|
| 第一段 | 简单装置 | 举例+因果 |
| 第二段 | 精密仪器的原理 | 实验推理+类比 |
| 第三段 | 地震波分类 | 科学分类 |

### 3. 文化背景

- 地震仪的发明是地震学的基础
- 纵波（P波）和横波（S波）的区别是地震学核心知识
- 通过地震波研究地球内部结构是地球物理学的重要方法

### 4. 修辞分析

- "like a thief in the night"——明喻，生动形象
- "neither slumbered nor slept"——双重否定，文学化表达
- "like a bluebottle buzzing round the room"——幽默类比

## 七、课后练习要点

1. **词汇练习**：掌握 slumber、rigid、seismometer、longitudinal、transverse 等核心词
2. **语法练习**：neither...nor... 双重否定；强调句型；虚拟条件句
3. **翻译练习**：注意科学术语的准确翻译；强调句的处理
4. **写作练习**：模仿从简单到复杂的说明文结构，介绍一种科学仪器

## 八、本课小结

本课介绍地震仪的发明原理和地震波的分类。核心内容：**地震仪利用惯性原理（重物保持静止）来记录地震波，地震波分为纵波、横波和主波三种**。文章从简单装置讲起，通过日常实验推理说明精密仪器的原理，最后科学分类三种波。语法重点为 neither...nor... 双重否定和强调句型。