A 7.4-magnitude earthquake jolted Japan this week and set off a tsunami warning, but shoppers at one grocery store simply steadied their carts and kept browsing as the building shook. Within hours, Tokyo’s subways were once again packed and bullet trains had resumed journeys near the epicenter.

本周，日本发生7.4级强震并引发海啸预警，但在一家超市里，顾客只是扶稳购物车，在房子晃动时继续挑选商品。几小时内，东京的地铁再次挤满了人，震中附近的新干线列车也恢复了运行。

“It’s happened so many times, I think it’s not a big deal,” said Hiroyuki Utsunomiya, 77, who runs a trucking company in the northeastern city of Ishinomaki.

“这种事发生太多次了，我觉得没什么大不了的，”77岁的宇都宫宏之（音）说，他在东北城市石卷经营一家货运公司。

Japan is one of the most seismically active parts of the world, with an average of two to three quakes each day. For many people in the country, tremors are not extraordinary and life tends to swiftly return to normal after an earthquake.

日本是全球地震最活跃的地区之一，平均每天会发生两到三次地震。对许多日本人来说，地震没什么大惊小怪的，地震过后生活通常会很快恢复正常。

But after the quake on Monday, the national meteorological agency urged people to be prepared for a more destructive earthquake. It warned that there was an elevated risk of a “megaquake” — magnitude 8 or higher — in northeastern Japan in the following week.

但在周一的地震之后，日本气象厅敦促民众为可能发生更具破坏性的地震做好准备。该机构警告说，未来一周内，日本东北地区发生8级或以上“强烈地震”的风险升高。

It is not possible to predict earthquakes and only probabilities can be calculated, according to the U.S. Geological Survey. The Japan Meteorological Agency is candid about the limitations of its advisories. “This information is extremely uncertain,” the agency said on Monday. A megaquake might not hit at all or there might be one after the advisory expires in a week, it added.

根据美国地质调查局的说法，地震无法预测，只能计算发生的概率。日本气象厅也坦言其预警存在局限性。“这些信息极其不确定，”该机构在周一表示。它还说，强烈地震可能根本不会发生，也可能在这一周的预警期结束后发生。

The megaquake advisories were designed after a 2011 earthquake devastated Japan as a way of encouraging preparations, officials said.

官员们表示，强烈地震预警系统是在2011年那场重创日本的地震之后设计的，目的是鼓励民众提前做好准备。

The advisory system for the Nankai Trough, a seismically active zone off southern Japan, began in 2019. A second system was created in 2022 for a zone off northeastern Japan where Monday’s quake struck. The advisories are rare, though. Together, the systems have generated only two other alerts.

针对日本南部外海地震活跃带南海海沟的预警系统于2019年启动。2022年的时候，针对周一发生地震的日本东北外海区域创建了另一个预警系统。不过，这类预警非常少见，两套系统加起来此前只发布过两次警报。

Both systems note the increased probability of a megaquake based on historical data. On Monday, the agency assessed that the chance of such a quake in northeastern Japan had risen to 1 percent from the base-line 0.1 percent — a tenfold increase in probability.

这两个系统都是基于历史数据来判断发生强烈地震的概率上升。本周一，日本气象厅评估认为，日本东北地区发生此类地震的概率已从基准的0.1%升至1%——增加了十倍。

For the authorities in Japan, where most structures are built with earthquakes in mind, even the slight rise in probability of a catastrophe merited the warning.

对于日本当局而言，在这个大多数建筑在建造时就考虑了抗震因素的国家，即便灾难发生概率只是略有上升，也值得发出预警。

Since the latest advisory was issued on Monday, officials in the northeastern city of Kuji have sent alerts three times a day — via radio, messaging apps and email — reminding residents to keep emergency kits ready and prepare to seek shelter anytime.

自周一发布最新预警以来，东北城市久慈的官员每天通过广播、即时通讯应用和电子邮件发送三次提醒，督促居民随时备好应急包，并做好随时避险的准备。

“We are raising awareness and disseminating information in a way that does not cause too much panic,” said Teruki Maeno, a crisis management official in Kuji, a city in Iwate prefecture.

“我们在提高公众意识、传播信息的同时，也尽量避免引发过度恐慌，”岩手县久慈市的一名危机管理官员前野辉树（音）表示。

周一地震后，日本东北部仙台市显示新干线停运通知的显示屏。

This balance — vigilance without panic — is the result of living with earthquakes for centuries. The consequences of Japan’s geology are everywhere: skyscrapers built on shock-absorbing rubber pads; early warning systems that can halt bullet trains seconds before tremors arrive; and generations who grew up doing regular earthquake drills in school.

这种“保持警惕但不恐慌”的平衡是日本人数个世纪以来与地震共存的结果。日本的地质条件带来的影响无处不在：建在减震橡胶垫上的摩天大楼；可以在震动到来前几秒让新干线停车的预警系统；一代又一代的日本人从小就在学校里定期参加地震演习。

The most devastating earthquakes have shaped how life, cities and architecture have developed in modern Japan. Experts say this focus on readiness helps explain why there were so few injuries on Monday, even though a similarly powerful earthquake could have leveled towns in another country.

最具破坏性的地震塑造了现代日本的生活、城市和建筑发展方式。专家表示，这种对防范的重视有助于解释，为什么本周一的地震虽然威力强大——同样的地震如果发生在其他国家可能会夷平整座城镇——却几乎没有造成人员伤亡。

“Ishinomaki has sturdy buildings that are rebuilt in the bedrock,” said Mr. Utsunomiya, whose office was swept away by the tsunami unleashed by the 2011 Fukushima quake. “It won’t budge.”

“石卷的建筑非常坚固，都是建在基岩之上的，”宇都宫宏之说。他的办公室曾在2011年福岛地震引发的海啸中被冲毁。“建筑不会轻易动摇。”

That earthquake and the resulting tsunami killed more than 19,000 people and led to a nuclear disaster. The Fukushima catastrophe is fresh in the memories of people in northeastern Japan.

2011年那场地震及其引发的海啸造成超过1.9万人遇难，并导致了核灾难。福岛灾难至今仍深深印在日本东北地区民众的记忆中。

“This region has lived with the threat of tsunamis since ancient times,” said Mr. Maeno, the Kuji city official. “The lessons learned from the past have been passed down through generations.”

“这个地区自古以来就一直生活在海啸威胁之下，”久慈市官员前野辉树说，“从过去吸取的教训是一代代传承下来的。”

But that confidence has its limits. The small tsunami wave — under three feet tall — that reached the coast of Iwate on Monday caused little concern. Had the authorities warned of something even bigger, Mr. Maeno said, the mood would have been completely different.

但这种从容也并非没有边界。周一到达岩手海岸的海啸浪高不足一米，并未引起太多担忧。前野辉树表示，如果当局预警的是更大的海啸，民众的反应就会完全不同。

“Everyone would panic,” he said.

“所有人都会恐慌，”他说。

周二，日本大船渡市，一名渔民准备出海。此前一天，地震引发了海啸预警。

It is for this reason, officials said, that the Japanese authorities take care with their earthquake advisories. If the tone is too alarming, they could cause the kind of panic that paralyzes life and the economy. If it’s too vague, nobody would pay attention.

官员们表示，也正因为如此，日本当局在发布地震预警时格外谨慎。如果语气过于危言耸听，可能引发瘫痪生活和经济的恐慌；如果过于含糊，则没人会在意。

The 1 percent chance the agency warned of on Monday was carefully calibrated. It indicated that the risk of catastrophe was elevated but low enough to keep the economy running normally, said Hiroki Muramatsu, a cabinet official who oversees disaster prevention.

气象厅周一提出的1%概率是经过精心权衡的。负责灾害防控的内阁官员村松宏树（音）表示，这一数字既表明灾难风险有所上升，同时又足够低，不至于影响经济的正常运转。

“Simply saying ‘it’s dangerous’ won’t get anyone to act,” said Hiroshi Ueno, an earthquake specialist at the Japan Meteorological Agency, referring to the probability-based warnings. “So we thought it would be more reliable to have some kind of numerical data.”

日本气象厅的地震专家上野宽在谈到基于概率的预警方式时说：“单纯说‘很危险’不会让任何人采取行动。所以我们认为，提供某种量化数据会更可靠。”

At the port in Kuji, Takuro Kokami, a fishery association official, said that fishermen reacted in different ways to the tsunami warning after the earthquake on Monday. Some took their boats out to sea instead of evacuating, hoping to protect their vessels from the waves, he said.

在久慈港，当地渔业协会负责人小高拓郎（音）表示，周一地震后发布海啸预警时，渔民的反应各不相同。他说，有些人为了保住渔船，没有选择撤离，而是把船开到了海上。

“This is entirely a matter of individual responsibility and judgment,” he said.

“这完全是个人自己的事，自己判断、自己负责，”他说。

Mr. Kokami said he takes a different approach: Evacuate first, get back to work later.

小高拓郎表示，他采取了不同的做法：先撤离，之后再回来工作。