The damage inflicted on Manhattan by an army of marauding extra-terrestrials and the superpowered defenders of Earth in blockbuster comic book movie Avengers Assemble would cost $160bn to repair, according to US "disaster experts".

Analysts for the Kinetic Analysis Corp, which assesses and predicts the cost of catastrophic incidents in the US, told the Hollywood Reporter that the climactic denouement to Joss Whedon's superpowered tale would cost more than 9/11 ($83bn), Hurricane Katrina ($90bn) or the Japanese tsunami ($122bn) to fix. Much of the repair bill would go on restoring Grand Central Station to its former glory, while fixing crushed tops of buildings would also add up.

"The extensive damage to Grand Central Terminal could prove highly disruptive, depending on the subsurface damage to the subway system," KAC said in a report for the industry bible. "Although such damage is unlikely, as the 9/11 events showed, collapsing buildings can cause significant damage to subsurface infrastructure such as gas, communications and electrical systems. Detailed site surveys will be required to assess the state of the subterranean infrastructure."

Analysts pointed out that claimants might be able to recoup losses by ticking the "act of God" box on their insurance forms, because both Thor and Loki, who appear as opponents in Avengers Assemble (titled simply The Avengers outside the UK) are considered gods in some cultures. "That designation would be subject to strenuous theological and legal debate," said a spokesman.

Avengers Assemble has taken a staggering $700m worldwide in its first two weeks of release and is on course to be one of the biggest films of the year at the box office. However, that amount looks rather puny compared to the cost of repairing Manhattan. Luckily, the real New York suffered no known damage in the making of the film.

One man who won't have to count his pennies so regularly in the wake of Avengers Assemble's success is director Whedon, who has his first major big screen smash at the age of 47 after a career spent largely as the creator of offbeat fantasy TV such as Buffy the Vampire Slayer and Firefly. The director yesterday posted a thank you letter to fans on his Whedonesque blog for supporting him through what he clearly does not see as the wilderness years.

"A lot of stories have come out about my 'dark years' and how I'm 'unrecognised'. I love these stories, because they make me seem super-important, but I have never felt the darkness (and I'm ALL about my darkness) that they described," wrote Whedon. "What doesn't change is that I've had the smartest, most loyal, most passionate, most articulate group of – I'm not even gonna say fans. I'm going with 'peeps' – that any cult oddity such as my bad self could have dreamt of. When almost no one was watching, when people probably should have STOPPED watching, I've had three constants: my family and friends, my collaborators (often the same), and y'all."

Whedon added that his proudest achievement with regard to Avengers Assemble was not the gargantuan box office, but rather the fact that he managed to get the words "mewling quim" into a major Hollywood blockbuster.