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Description
Michael Pentz introduces the unit. Russell Stannard introduces his discussion on P and S waves in earthquakes with a brief definition of the two kinds of waves (compressional and transverse waves).
... Ian Gass discusses the effect of P and S waves on the earth.
| 51 | 00:04:19,000 | 00:04:25,000 | ..at right angles to the line of the fault. Okay here we go. |
| 52 | 00:04:27,000 | 00:04:31,000 | As you saw, the movement was a side to side movement. |
| 53 | 00:04:32,000 | 00:04:34,000 | In other words, an S wave. Let’s do it again. |
| 54 | 00:04:36,000 | 00:04:39,000 | Forget about any reflections that you see coming back along… |
| 55 | 00:04:40,000 | 00:04:42,000 | ..the springs from the support, it’s obviously got nothing to do with it. |
| 56 | 00:04:43,000 | 00:04:47,000 | So there we are, at right angles to the line of the fault we have S waves. |
| 57 | 00:04:48,000 | 00:04:52,000 | Now how about here? How about along the line of the fault and… |
| 58 | 00:04:53,000 | 00:04:59,000 | ..in the direction in which I’m going to move the block? Okay here we go. |
| 59 | 00:05:01,000 | 00:05:04,000 | Right, well once again forget about the reflection. |
| 60 | 00:05:05,000 | 00:05:08,000 | What you saw was a compressional pulse moving along, |
| 61 | 00:05:09,000 | 00:05:12,000 | the springs closed up as I pushed the block against them… |
| 62 | 00:05:13,000 | 00:05:17,000 | ..and it was this bunching effect which you saw moving along. Let’s try it again. |
| 63 | 00:05:19,000 | 00:05:21,000 | Once more. |
| 64 | 00:05:24,000 | 00:05:26,000 | Okay, well let’s see that in slow motion now. |
| 65 | 00:05:31,000 | 00:05:33,000 | Here comes the pulse. |
| 66 | 00:05:36,000 | 00:05:39,000 | Just move the spring back to where it was. |
| 67 | 00:05:40,000 | 00:05:42,000 | Repeat it once again, there we are. |
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