TOKYO, NOV. 2 -- Ten days before the coronation of Emperor Akihito, this traditionally safe city is girding for violence amid an escalation of terrorist attacks blamed on anti-monarchist radicals.

Government officials, reacting to the bombing of a policemen's dormitory Thursday night that killed one officer and injured six, said today that they were considering invoking a 1952 law that would give the police sweeping powers to detain radicals and block demonstrations.

"We'll tighten security even if the public criticizes it as excessive," said Home Minister Keiwa Okuda, who chairs a committee that oversees the nation's police forces.

Justice Minister Seiroku Kajiyama said the government must "seriously discuss" whether to take the unprecedented step of invoking the anti-subversive activities law, which among other things would allow the authorities to jail radicals for advocating acts of disruption or violence, even before any such acts were committed.

The vows of a new crackdown came after Japanese authorities had already begun mobilizing one of the most intensive security operations since the end of World War II. The effort is aimed at protecting not only Akihito, but also the dignitaries from 153 countries planning to attend the emperor's Nov. 12 enthronement, including Vice President Quayle and Britain's Prince Charles.

Police officials said this week that they intend to deploy 37,000 officers in Tokyo on the day of the coronation, including 5,000 recruited from neighboring jurisdictions. They also said they will probably conduct extensive searches of people lining Akihito's parade route.

On Thursday, 40 police frogmen searched the moat around the Imperial Palace for bombs. The normally peaceful area surrounding the palace grounds is ringed with armored police buses and vans.

The moves are aimed primarily at a group called the Chukakuha, or Middle Core Faction, which has an estimated 5,000 members, perhaps 400 of them underground.

The group has vowed to violently disrupt Akihito's enthronement and assassinate the imperial family, seeing it as an opportunity to strike a blow against the most important symbol of the Japanese political, social and economic system.

Although not nearly so big as the leftist groups that fought police in the 1960s and 1970s, Chukakuha has proven itself a force to be reckoned with. In May 1986, it launched a homemade missile that narrowly missed the palace in which the leaders of the seven major industrial nations, including then-President Reagan, were meeting.

Earlier this year, a Chukakuha missile struck the residence of Prince Hitachi, the emperor's brother; the projectile did not injure anyone but caused considerable damage. "Akihito, next time it's your turn. We have trained our {gun} sights on your heart," the group declared.

Radicals have also exploded bombs in several Shinto shrines and the homes of prominent Japanese citizens this year.

No group has claimed responsibility for Thursday night's bombing of the police dormitory, but authorities said they have little doubt that members of Chukakuha or a closely related group were behind the bombings.