With a Better Understanding of Physics, We Could Predict Volcanic Eruptions
With a Better Understanding of Physics, We Could Predict Volcanic Eruptions
随着对物理学理解的加深，我们或许能预测火山喷发
In the summer of 1991, Pinatubo, a volcano in the Philippines, self-destructed. The eruption started on June 12, and three days later it culminated in a tremendous explosion. By the time pyroclastic flows—incandescent avalanches of molten rock and gas—tumbled down its sterilized slopes, Pinatubo’s peak had been obliterated and replaced by a 2.5-kilometer-wide chasm. 1991年夏天，菲律宾的皮纳图博火山（Pinatubo）发生了自我毁灭式的喷发。喷发始于6月12日，三天后演变成一场巨大的爆炸。当火山碎屑流——即炽热的熔岩和气体雪崩——从其寸草不生的山坡上倾泻而下时，皮纳图博的山峰已被彻底摧毁，取而代之的是一个宽2.5公里的巨大深坑。
The eruption killed more than 800 people, mainly because roofs, weighed down by rain-saturated ash, collapsed. But it could have been so much worse: About 250,000 people, across multiple cities and a sprawling US Air Force base, lived in the volcano’s shadow. When Pinatubo started convulsing and belching steam in April of that year, scientists from the US and the Philippines deployed an array of instruments that tracked the volcano’s inner tumult. 这次喷发造成了800多人死亡，主要原因是屋顶被雨水浸透的火山灰压垮。但情况本可能更糟：当时约有25万名居民生活在这座火山的阴影下，分布在多个城市和一个庞大的美国空军基地中。同年4月，当皮纳图博火山开始震动并喷出蒸汽时，来自美国和菲律宾的科学家部署了一系列仪器，追踪火山内部的动荡。
“We didn’t know much about that volcano, and so there was this really rapid geological assessment. And the assessment said, ‘Oh, crap, when this thing erupts, it only erupts big,’” says Mike Poland, current scientist in charge at the US Geological Service’s Yellowstone Volcano Observatory. “And that became the basis for a forecast.” “我们当时对那座火山知之甚少，所以进行了一次非常快速的地质评估。评估结果显示：‘糟糕，这家伙一旦喷发，规模必然巨大，’”美国地质调查局黄石火山观测站现任负责人迈克·波兰（Mike Poland）说，“这成为了我们做出预报的基础。”
By early June, ash and lava were escaping Pinatubo’s flanks, and an evacuation was ordered, just a few days before the cataclysmic hammer fell. It was, in other words, a very close call. 到6月初，火山灰和熔岩开始从皮纳图博的山侧溢出。就在灾难性喷发发生的前几天，当局下达了撤离命令。换句话说，这是一次极其惊险的避险。
Those scientists saved countless lives, but their forecast was more of an educated guess than it might have appeared. It was nothing like a weather forecast; they couldn’t say with anything resembling certainty that on June 12 an explosive eruption was going to occur, nor could they predict the evolution of that eruption. 那些科学家挽救了无数生命，但他们的预报与其说是科学预测，不如说更像是一种基于经验的推测。这与天气预报完全不同；他们无法确定地预言6月12日一定会发生爆炸性喷发，也无法预测喷发过程将如何演变。
With very few exceptions, this imprecision is true of all well-monitored volcanoes. But volcanology, as a field, has made great leaps since Pinatubo blew its top. The instrumentation is more advanced, machine learning has made interpreting data far more efficient, and scientists have a much better understanding of the magmatic plumbing that drives volcanism. That’s prompted me—as a professionally trained volcanologist who now writes a lot about the field—to wonder: How close are we to forecasting volcano behavior the way we forecast the weather? 除了极少数例外，这种不确定性适用于所有受到严密监测的火山。但自皮纳图博火山喷发以来，火山学领域已经取得了巨大飞跃。仪器设备更加先进，机器学习使数据解读效率大幅提升，科学家们对驱动火山活动的岩浆管道系统也有了更好的理解。作为一名受过专业训练、现在经常撰写相关领域文章的火山学家，我不禁思考：我们距离像预报天气那样预测火山行为还有多远？
Today, we know that a storm of a certain magnitude will fall on a specific city in a few days’ time. Will scientists ever be able to say that a week from now, a certain volcano has an 80 percent chance of erupting in a particular way—with lava gushing, with a certain explosive force, with pyroclastic flows that will travel down its western flank? I asked around, and I found both skepticism and a surprising degree of optimism. “The short answer—otherwise I wouldn’t be doing this—is yes,” says Diana Roman, a volcanologist at Carnegie Science in Washington, DC. 今天，我们知道某场特定强度的风暴将在几天后袭击某个城市。科学家未来是否也能预言：一周后，某座火山有80%的概率以特定方式喷发——比如熔岩喷涌、具备某种爆炸强度、火山碎屑流将沿西侧山坡流下？我四处询问，发现既有怀疑的声音，也有令人惊讶的乐观态度。华盛顿特区卡内基科学研究所的火山学家戴安娜·罗曼（Diana Roman）说：“简短的回答是——否则我也不会从事这项研究了——是的。”
Though sky watchers have anticipated the weather for millennia, contemporary scientific prediction of weather is a recent invention: The first mathematical equations grounding these models were derived at the start of the 20th century. Today, meteorologists can take a pandemoniac system—Earth’s atmosphere, oceans, and landforms—and make accurate forecasts up to two weeks into the future. 尽管人类观测天象已有数千年历史，但现代科学意义上的天气预报却是近期的发明：支撑这些模型的第一批数学方程是在20世纪初推导出来的。如今，气象学家可以利用地球大气、海洋和地貌这一混乱系统，做出长达两周的准确预报。
Weather affects more people than volcanism—namely, everyone, all the time—but some 800 million people live within 100 kilometers of an active volcano, and some (very rare) eruptions can also affect the entire planet. Both weather and volcanism are complex systems that we want to understand, but the problems they present for forecasting are different. 天气对人类的影响比火山活动更广泛——即每个人、每时每刻都在受其影响——但仍有约8亿人生活在距离活火山100公里的范围内，且某些（极罕见的）喷发甚至会影响整个地球。天气和火山活动都是我们试图理解的复杂系统，但它们在预测方面带来的挑战各不相同。
“The big difference between [volcanoes] and the weather forecasting is the weather is always happening,” says Jenni Barclay, a volcanologist at the University of Bristol in England. The atmosphere is perpetually visible and measurable to meteorologists. “Even they would say they need more observations.” Magma, on the other hand, resides kilometers below Earth’s crust, and at most, active volcanoes erupt once every few decades. “火山与天气预报的最大区别在于，天气时刻都在发生，”英国布里斯托大学的火山学家珍妮·巴克莱（Jenni Barclay）说。对于气象学家而言，大气层是始终可见且可测量的。“即便如此，他们也会说需要更多的观测数据。”而岩浆则深藏在地球地壳下数公里处，且活火山最多几十年才喷发一次。
Each volcano is also unique. The architecture of the subterranean pathways that funnel magma to the surface, the chemistry of the magma, the cadence of eruptions, and the assortment of eruption styles differ from place to place. And eruptions don’t have just one trigger. The temperature and pressure of the magma reservoir, the weakness of the enclosing rock, the gas and crystal content, the depth of the magma, the regional motion of tectonic plates—these factors all contribute to whether a paroxysm happens or fizzles out. 此外，每座火山都是独特的。将岩浆输送到地表的地下通道结构、岩浆的化学成分、喷发的节奏以及喷发类型的多样性，在不同地点各不相同。而且，喷发并非只有一个触发因素。岩浆库的温度和压力、围岩的脆弱程度、气体和晶体含量、岩浆深度、构造板块的区域运动——这些因素共同决定了火山是会剧烈爆发还是最终平息。
“Geology is chaotic,” says Marius Isken, a geophysicist at the GFZ Helmholtz Center for Geosciences in Potsdam, Germany. But there is order buried in the chaos. Can we find it? “地质学是混乱的，”德国波茨坦GFZ亥姆霍兹中心的地质物理学家马里乌斯·伊斯肯（Marius Isken）说。但在混乱之中埋藏着秩序。我们能找到它吗？
I imagine volcanoes as orchestras composed of hundreds of different instruments. Forecasting eruptions isn’t about hearing the music. We already do that: Seismometers sense the cracking of rock as magma ascends; ground sensors and satellites can track shifts in the crust, indicating where magma is flowing; gas detectors reveal when magma rises to shallow depths, depressurizes, and emits noxious fumes. 我将火山想象成由数百种不同乐器组成的管弦乐队。预测喷发不仅仅是听音乐。我们已经能做到这一点：地震仪能感知岩浆上升时岩石的破裂；地面传感器和卫星可以追踪地壳的位移，指示岩浆的流动方向；气体探测器能揭示岩浆何时上升到浅层、压力降低并释放出有毒气体。
The challenge comes in knowing how the symphony will develop to a climax, long before it gets underway. Today, at the most comprehensively monitored volcanoes, the best that volcanologists can normally offer is not prediction but a form of acute caution. Often, alert systems—including those used by the US Geological Survey—notify the public if a volcano is exhibiting heightened or escalating unrest. But that doesn’t mean a 挑战在于，如何在交响乐进入高潮之前，预知它将如何发展。如今，在监测最全面的火山上，火山学家通常能提供的最好结果并非“预测”，而是一种高度警示。通常，预警系统（包括美国地质调查局使用的系统）会在火山表现出加剧或升级的动荡时通知公众。但这并不意味着……