Scientists have found a way to estimate an earthquake's ultimate strength by analyzing¹ the initial seconds of a rupture² -- a step that could one day provide early earthquake warning.

Currently, a quake's magnitude -- or how much energy is released is determined³ after the shaking stops, usually minutes after an event.

But researchers from the University of California, Berkeley, say the measurements of seismic⁴ waves soon after a temblor can signal whether it will be a minor⁵ or monster temblor.

They say the information could possibly be used in an alert system to give seconds to tens of seconds of advance notice of an impending⁶ quake -- enough time for schoolchildren to take cover, power generators⁷ to trip off and valves to shut on pipelines⁸.

"We're not taking about a massive amount of time," said Richard Allen, an assistant professor of earth and planetary science, who led the study.

"But one can use our approach to come up with a magnitude before people have felt the ground shaking."

Details appear in Thursday's issue of the journal Nature.

美国研究人员最近发现了通过分析地震发生之初的前几秒的震波大小，便可以断定出地震最终强度的方法，从而为未来总有一天能够早些提供地震警报迈出了一步。

据美联社11月9日报道，目前，地震震级或释放出多少能量只能在地震停止后才能确定。但是，美国加利福尼亚大学的研究人员说，在地震刚刚发生之后产生的震波大小便可显示出这次地震最终是小还是大。

这些研究人员说，这一信息可用于警报系统，即提前几秒钟或数十秒钟发出地震已迫在眉睫的警报，从而能有足够的时间使孩子们躲到安全的地方，使电机和管道阀关闭。

地球和行星学助理教授理查德-艾伦说：“我们不能争得很长的时间。但是，我们可以利用这一方法使人们在感到地面在晃动之前向他们提供震级的大小。”

在这项研究中，艾伦和他的同事们分析了过去几十年在太平洋边缘地带发生的71次较大地震的记录，其中21次地震超过6级。

关于这项研究的详细报道，刊登在11月10日出版的英国《自然》杂志上。