第3019期:Earthquake early warning system reduces message latency

So, both along the fault, we like those sensors really close the fault because that gives us really those first motions that are coming out of the earthquake.这两个传感器都紧贴断层，我们很喜欢紧贴断层的传感器，因为这样能让我们真正捕捉到地震最初的震动情况。It tells us the earthquake has started. So, once that earthquake started, seismic waves start travelling away from where that earthquake starts.这样我们就知道地震发生了。一旦地震开始发生，地震波就会从地震起始处向外传播。'P waves' or primary waves are the first waves that arrive. They're faster and you feel sort of a jolt coming up beneath you.“P波”或“初至波”最先到达观测点，传播速度很快，你会感觉到脚下有种震动感。The 'S waves' would travel along behind those and start shaking you back and forth.“S波”会紧随其后，让你来回摇晃。So, we're in Pasadena and we're at one of the seismic stations. At the bottom of this vault, this is what it is.我们正在帕萨迪纳的一个地震监测站。在这个小仓库的地下，这就是传感器。So, and it moves relative to the earth and basically whatever happens in here, gets turned into an electrical signal and boom.这个传感器会随地面一同移动，基本上，无论地表发生什么运动，它都能将其转化为电信号。It takes some very, very precise observation about what's happening.要记录这些运动需要非常精密的监测。We were one of the early adopters of the ShakeAlert system. We implemented it in January of 2017.我们是早期采用ShakeAlert系统的机构之一。我们于2017年1月启用了该系统。And it gives us precious seconds to anticipate an earthquake that may be coming to Los Angeles area and that will enable us to put an alert out to our operators.它能让我们争取到宝贵的几秒钟时间来预判可能会袭击洛杉矶地区的地震，还能让我们向工作人员发出警报。Part of the protocol is to slow down the train as it is moving in advance of an earthquake.<p style="color:#333333;font-weight:normal;font-size:16px;line-height:30px;font-family:Helvetica,Arial,sans-s