A、Earthquakes may happen anywhere at anytime. B、The precise place and time of an earthquake. C、Whether the majority of people kn

Earthquakes may rightly be ranked as one of the most destructive forces known to man: since records began to be written down, it has been estimated that earthquake related fatalities have numbered in the millions, and that earthquake related destruction has been beyond calculation. The greater part of such damage and loss of life has been due to collapse of buildings and the effects of rockslides, floods, fire, disease, tsunamis, and other observable events resulting from earthquakes, rather than from the quakes themselves.
    The great majority of all earthquakes occur in two specific geographic areas. One such area covers the Pacific Ocean and its bordering landmasses. The other extends from the East Indies to the Atlas Mountains, including the Himalayas, Iran, Turkey, and the Alpine regions. It is in these two great belts or zones that ninety percent of all earthquakes take place; they may, however, happen anywhere at any time.
    This element of the unknown has for centuries added greatly to the dread and horror surrounding earthquakes, but in recent times there have been indications that earthquake forecast may be possible. By analyzing changes in animal behavior, patterns of movements in the earth’s shell, variations in the earth’s force of attraction, and the frequency with which minor earth shakes are observed, scientists have shown increasing success in expecting when and where earthquakes will strike. As a result, a worldwide earthquake warning network is already in operation and has helped to prepare for(and thus lessen)the vast destruction that might otherwise have been totally unexpected.
16. What may cause the greater damage in earth’ quakes according to the speaker?
17. According to the speaker, what is the unknown element that adds dread and horror to people?
18. According to the speaker, what can we learn about the scientists?