第三篇 Unpredictable Earthquake
Humans are forever forgetting that they can’t control nature. Exactly 20 years ago, a Time magazine cover story announced that "scientists are on the verge of being able to predict the time, place and even the size of earthquakes." The people of quake-ravaged (被地震破坏的) Kobe learned last week how wrong that assertion was.
None of the methods conceived two decades ago has yet to discover a uniform wanting signal that preceded all quakes, let alone any sign that would tell whether the coming temblor (地震) is mild or a killer. Earthquake formation can be triggered by many factors, says Hiroo Kanamori, a seismologist (地震学家) at the California Institute of Technology. So, finding one all-purpose warning sign is impossible. One reason: Quakes tart deep in the earth, so scientists can’t study them directly. If a quake precursor were found, it would still be impossible to ward humans in advance of all erous quakes. Places like Japan and California are riddle with hundreds, if not thousands, of minor faults.
Prediction would be less important if scientists could easily build structures to withstand tremors. While seismic engineering has improved dramatically in the past 10 to 15 years, every new quake reveals unexpected weakness in "quake-resistant" structures, says Terry Tullis, a geophysicist at Brown University. In Kobe, for example, a highway that opened only last year was damaged. In the Northridge earthquake, on the other hand, well-built structures generally did not collapse.
A recent report in Science adds yet more anxiety about life on the faulty lines. Researchers Fan computer simulations to see how quake resistant buildings would fall in a moderate size temblor, taking into account that much of a quake’s energy travels in a large "pulse" of focused shaking. The results: both steel-frame buildings and buildings that sit on insulating rubber pads suffered severe damage.
More research will help experts design stronger structures and possibly find quake precursors. But it is still a certainty that the next earthquake will prove once again that every fault cannot be monitored and every highway cannot be completely quake-proofed. 第三篇 Unpredictable EarthquakeAccording to the passage all the following statements are TRUE except ______.