Tokyo tiptoed into the bidding race after losing out to Rio de Janeiro for 2016 and with the country still recovering from a deadly tsunami and resulting nuclear crisis in 2011.
"You can't predict with any certainty where and when earthquakes will hit," Tokyo's bid president Tsunekazu Takeda told reporters.
"They can potentially happen in any country. It's the reaction to the quake which is the most important thing and to be ready as a nation if that occurs."
Tokyo, which hosted Asia's first Olympics in 1964, is the favourite with British bookmaker William Hill to beat rivals Istanbul and Madrid, offering odds of 4/6. Istanbul are 5/2 and Madrid 3/1.
Despite Tokyo's economic strength and strong infrastructure, Takeda faced questions over whether the city could withstand another major earthquake.
A 9.0-magnitude quake in March 2011 triggered tsunami waves of up to 40 metres, killing more than 15,000 people in northeast Japan and causing a meltdown at a nuclear plant north of Tokyo.
"In Japan, the procedures for dealing with disasters and architectural guidelines are very stringent," said Takeda. "In the 2011 disaster there were no casualties in Tokyo.
"The buildings really didn't suffer damage. We stressed to the IOC (International Olympic Committee) that Tokyo's buildings can withstand earthquakes.
"Tokyo's government is also working on making sports facilities even more quake-proof and seven years from now they certainly will be," he said as the city unveiled its bold, waterside plan for the 2020 Olympics.
All three cities - Madrid bidding for a third consecutive time and Istanbul a fifth - submitted their candidature files to the IOC in Lausanne on Monday.
"Tokyo is the world's most forward-thinking city," said Japanese Olympic Committee chief Takeda. "It sets global trends in everything from technology to fashion.
"Many of our venues are in place. Most of the Games infrastructure is in place. The budget is already in the bank for a Games in the capital of the future."
The jewel in Tokyo's glossy 2020 brochure was a space-age makeover of National Stadium, the main venue for the 1964 Games which symbolised Japan's recovery from its war-time defeat.
The 80,000-capacity venue, which resembles a flying saucer, will feature a retractable roof - a first for a main Olympic stadium - and moveable seats.
"We will use the stadium from 1964 and improve it for 2020," said Takeda. "It will be there for another 50 years which would be around 100 years. That legacy is an important point."
New Tokyo governor Naoki Inose underlined the city's credentials, pointing to the full backing of the government of Shinzo Abe, who returned as Prime Minister last month.
Abe himself was appointed as the Tokyo 2020 bid's supreme advisor on Tuesday.
"Tokyo has a budget of 12 trillion yen," said Inose, referring to the Tokyo Metropolitan Government's financial base. "That's quite big."
Inose added: "Tokyo has a superb transport system, its railway network can handle 25 million passengers daily without a second's delay."
The Tokyo governor said he had been inspired by watching Usain Bolt storm to Olympic gold last year.
"I will never forget the 100 metres final in London," he said. "Bolt's attitude at the start and the way he burst out of the blocks was spectacular.
"I'm no Usain Bolt but for Tokyo's campaign the starting point is crucial. We have communicated Tokyo's overwhelming edge in our candidature file. It's very thick."
The IOC will choose the host for the 2020 Olympic Games on September 7 in Buenos Aires.
- Sports & Recreation
- Politics & Government