练习材料
Lesson 42-5 Recording an earthquake
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.
/ˈlɛsən/ 42-5 /rəˈkɔrdɪŋ/ /ən/ /ˈɜrθˌkweɪk/
/ɪt/ /wəd/ /bi/ /ʌp/ /ənd/ /daʊn/, /tʊ/ /ənd/ /froʊ/ /ənd/ /frəm/ /saɪd/ /tə/ /saɪd/. /ˈɪnstrəmənts/ /həv/ /bɪn/ /dɪˈvaɪzd/ /ənd/ /kən/ /bi/ /soʊ/ /pleɪst/ /ðət/ /ɔl/ /θri/ /ˈɛləmənts/ /kən/ /bi/ /rəˈkɔrdəd/ /ɪn/ /ˈdɪfərənt/ /græfs/.
/wɛn/ /ði/ /ˈɪnstrəmənt/ /əz/ /ˈsɪʧuˌeɪtɪd/ /ət/ /mɔr/ /ðæn/ 700 /maɪlz/ /frəm/ /ði/ /ˈɜrθˌkweɪk/ /ˈsɛntər/, /ðə/ /ˈgræfɪk/ /ˈrɛkərd/ /ʃoʊz/ /θri/ /weɪvz/ /əˈraɪvɪŋ/ /wʌn/ /ˈæftər/ /ði/ /ˈʌðər/ /ət/ /ʃɔrt/ /ˈɪntərvəlz/. /ðə/ /fɜrst/ /rəˈkɔrdz/ /ði/ /əˈraɪvəl/ /əv/ /ˌlɑnʤəˈtudənəl/ /vaɪˈbreɪʃənz/. /ðə/ /ˈsɛkənd/ /mɑrks/ /ði/ /əˈraɪvəl/ /əv/ /trænzˈvɜrs/ /vaɪˈbreɪʃənz/ /wɪʧ/ /ˈtrævəl/ /mɔr/ /ˈsloʊli/ /ənd/ /əˈraɪv/ /ˈsɛvrəl/ /ˈmɪnəts/ /ˈæftər/ /ðə/ /fɜrst/. /ðiz/ /tu/ /həv/ /ˈtrævəld/ /θru/ /ði/ /ɜrθ/. /ɪt/ /wəz/ /frəm/ /ðə/ /ˈstʌdi/ /əv/ /ðiz/ /ðət/ /soʊ/ /mʌʧ/ /wəz/ /lɜrnt/ /əˈbaʊt/ /ði/ /ɪnˈtɪriər/ /əv/ /ði/ /ɜrθ/. /ðə/ /θɜrd/, /ɔr/ /meɪn/ /weɪv/, /ɪz/ /ðə/ /ˈsloʊəst/ /ənd/ /həz/ /ˈtrævəld/ /raʊnd/ /ði/ /ɜrθ/ /θru/ /ðə/ /ˈsɜrfəs/ /rɑks/.
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