科学家担忧日本会发生更多大地震

Significant aftershocks continue to shake Japan, more than two months after the magnitude 9.0 earthquake that triggered massive tsunami, leaving 25,000 people dead or missing and creating a catastrophe at a coastal nuclear power plant.

在日本发生九级大地震两个多月后，较强的余震仍时有发生。那场大地震引发了海啸，造成2万5000人死亡或失踪，并导致一座沿海核电站发生核灾难。

Five tremors in excess of magnitude 5.0 on the Richter scale have shaken Japan just this week. But scientists are warning that the largest expected aftershock has yet to hit. And, new, devastating inland quakes can also be expected.

仅在这个星期就有五个震级在里氏五级以上的余震发生。然而，科学家警告说，最大的余震还尚未发生，而且日本内陆也有可能会发生新的地震。

Japan hopes to never again hear these chilling words. An NHK announcer describing the scene on March 11 as a huge tsunami washes away homes, fishing trawlers and vehicles in coastal communities.

But scientists are cautioning that a repeat for Japan - on a smaller scale - is not a matter of if, but when.

科学家警告说，日本还会再次发生地震，这不过是早晚的问题，只不过规模会相对小一些。

After analyzing the magnitude 9.0 quake, scientists in Japan and the United States are making that sobering conclusion.

日本和美国的科学家在对这场九级大地震进行分析后得出了这样令人感到警醒的结论。

Several studies indicate the descending Pacific Ocean plate and the overlying plate on which Japan sits, slipped past each other by up to 60 meters. The research indicates five portions of the fault - covering more than 600 kilometers - were ruptured in the quake. That forebodes more seismic activity.

一些研究指出，下沉的太平洋板块和日本所处的位于上方的板块相互交错达60米。研究显示，断层中有五个区域在地震中发生断裂，这些发生断裂的断层涵盖600多公里的地区。这也就预示会有更多地质活动发生。

And, because the March 11 quake seems to have transferred stress along the same fault, some scientists are cautioning about a magnitude 8.0 closer to the Tokyo metropolitan area, home to more than 30 million people.

同时，由于3-11大地震把同一断层的压力转移，一些科学家发出警告，一场8.0级的地震会在更靠近东京大都会的地区发生。东京大都会地区居住着3000多万人口。

However, others offer a wider geographical target, as far to the north as Hokkaido.

但也有一些专家划定了一个范围更大的区域，北侧甚至到达北海道。

A frequently cited time frame, by some of Japan’s most senior seismologists, is between now and the next ten months.

日本一些资历最深的地质学家估计，这场地震发生的时间范围将是现在到未来10个月之间。

However, professor Takeshi Sagiya at Nagoya University’s Research Center for Seismology, Volcanology and Disaster Mitigation is cautious about that narrow chronology.

不过，名古屋大学地震、火山和减灾研究中心的鹭谷威教授对这样的短期预测持谨慎态度。

"I'm not quite sure about the basis of those specific kind of prediction about aftershocks," said Sagiya. "Those aftershocks happening are quite variable from place to place, from time to time. It can happen with a month, or within days, from the main shock. But also it can happen within some decades."

他说：“我不是很肯定这些有关对余震发生的具体预测的理论依据。余震发生的时间和地点都有很大差异。余震可以在主震发生后的一个月或者几天之内发生。但也可能会在几十年之内发生。”

Geophysicist Seth Stein of Northwestern University in the U.S. state of Illinois says the forecast intensity is in line with historical data but, like professor Sagiya, he is more comfortable expressing an extended timeline.

美国西北大学的地球物理学家赛斯.斯坦说，对余震强度的预测和历史资料像吻合。与鹭谷威教授一样，斯坦也认为余震会在更长的时间范围内发生。