On Sept. 1, 1923, a massive earthquake ripped through the Japanese port city of Yokohama and leveled much of Tokyo. The subsequent fires, tsunamis and aftershocks claimed the lives of 140,000 Japanese and foreigners. Millions were left homeless. Even though it was one of the greatest natural disasters in history, however, memories of it have been overshadowed in Japan by the firebombing of Tokyo and other cities during World War II, not to mention the destruction of Hiroshima and Nagasaki.

In “Yokohama Burning,” Joshua Hammer excavates this terrible event from oblivion. Hammer, a former correspondent for Newsweek and the author of “A Season in Bethlehem: Unholy War in a Sacred Place,” has pored over diaries, letters and documents and conducted numerous interviews. His zeal to produce a kind of cinéma vérité of the earthquake, in the form of anecdotes and short accounts, can become dizzying in places. He also tries to make too much out of minor American government officials or other characters whose obscurity is not a historical accident that needs to be remedied. But Hammer goes beyond simply recounting the earthquake’s aftermath to make a provocative and largely persuasive case that it marked a turning point in Japan’s embrace of militant nationalism.

Had the earthquake never occurred, the story of Yokohama would be fascinating enough. After Commodore Matthew Perry opened up shogun Japan with gunboat diplomacy in 1853, the sleepy fishing village of Yokohama became a foreign settlement, epitomizing the determination of Emperor Meiji, a Japanese version of Peter the Great, to import and emulate Western ideas. Countries like the United States and Britain set up consulates, while a motley crew of foreigners, including Chinese money-changers, English silk merchants, Spanish missionaries and Lebanese jewelers, piled into Yokohama around the turn of the century. Soon enough, it came to resemble Shanghai. Japanese nationalists, however, were incensed by the emergence of the bustling cosmopolitan city.

As Hammer notes, the divisions between traditionalists and modernizers extended even to earthquakes. The traditionalists clung to the notion that angry spirits were responsible for natural disasters, and resisted Western science. Hammer highlights the travails of Akitsune Imamura, a University of Tokyo seismologist who represented a new generation of scientists, trained by Western experts. Imamura, who predicted the timing and magnitude of the Yokohama quake 16 years in advance, came close to ruining his career. Government officials and academics dismissed him as an alarmist, and tried to force him to recant.

Once the earthquake erupted, the Japanese government was nowhere to be found. Americans and Britons on the scene carried out the lion’s share of the initial rescue work. Hammer shows that the emergence of modern communications, most importantly the telegraph, meant that the Yokohama disaster became the first modern international relief effort. But the Japanese authorities, intent on demonstrating that they didn’t require assistance, reportedly jammed the messages of American relief ships and tried to prevent them from docking. Nor were Japanese captains inclined to take on refugees stranded on beaches. According to Hammer, “historians looking back for clues to Japan’s psychology prior to World War II might begin here, in this key moment of interaction between the Japanese and their American would-be rescuers, when Japan’s peculiar pre-conflict combination of pride and insecurity was on full display.”

Indeed, in what Hammer sees as a dress rehearsal for World War II, the Japanese military seized upon the chaos to foment hatred of Koreans living in Japan. Thousands were murdered by street thugs. As Hammer observes, “although the killings appeared to have started spontaneously . . . the army in Tokyo and other areas whipped up rumors about Korean well poisonings and arson, and for several days gave vigilante squads known as Self-Defense Committees freedom to patrol the streets and exact what justice they saw fit.”

Given the virulence of Japanese nationalism, which today remains a potent cultural force that suppresses any effort to confront past war crimes, the militarist cabal would most likely have come to power even if the earthquake had not taken place. But it certainly harmed relations between the United States and Japan. Resentment over reports that the Japanese had failed to show much appreciation for American aid ended up heightening xenophobia on both sides of the Pacific. In 1924, President Calvin Coolidge, over the impassioned and prescient warnings of his ambassador to Japan, opportunistically signed the egregious Immigration Act, or National Origins Act, which in essence stigmatized the Japanese as an inferior race. The result was to infuriate Japan and bolster the power of the nationalists.

As the United States and Japan headed toward war, the lone survivor of their brief détente seemed to be the venerable Imperial Hotel, which had been designed by Frank Lloyd Wright and opened its doors on the very day of the earthquake. The large courtyard pool Wright insisted upon permitted the Imperial’s alert staff to douse numerous small blazes created by the earthquake and to save it. The hotel went on to survive World War II as well. Its reputed indestructibility added to its mystique, attracting celebrities like Babe Ruth and the honeymooning Marilyn Monroe and Joe DiMaggio. In the late 1960’s, old age led to the dismantling of the hotel, whose facade can now be viewed in a theme park devoted to the Meiji era. In illuminating this descent into militarism, Hammer’s fine book helps to ensure that Japan cannot dispose of the other, less savory parts of its past as tidily.