A ONE-WOMAN mission to prove breasts don't cause earthquakes has swollen into a shirt-straining global movement preparing for the inaugural "Boobquake".

Iranian cleric Hojatoleslam Kazem Sedighi angered womens' groups around the world on Monday when he claimed that promiscuous women were responsible for literally making the earth move.

"Many women who do not dress modestly ... lead young men astray, corrupt their chastity and spread adultery in society, which (consequently) increases earthquakes,'' Sedighi said.

"What can we do to avoid being buried under the rubble?'' he asked during a prayer sermon on Friday.

"There is no other solution but to take refuge in religion and to adapt our lives to Islam's moral codes.''

Women in the Islamic Republic are required by law to cover from head to toe, but Sedighi says an increase in young women flaunting the law - and not the fact that Tehran straddles scores of fault lines - is risking the lives of the city's 12 million inhabitants.

Jennifer McCreight is determined to prove him wrong.

Since launching the "Boobquake" Facebook page two days ago, she has enlisted more than 20,000 women promising to show as much cleavage as possible on Monday, April 26.

If the world doesn't then disappear into an apocalyptic fiery chasm, then Sedighi will have no option but to admit he was wrong.

"On Monday, April 26th, I will wear the most cleavage-showing shirt I own," Ms McCreight wrote.

"Yes, the one usually reserved for a night on the town.

"I encourage other female skeptics to join me and embrace the supposed supernatural power of their breasts. Or short shorts, if that's your preferred form of immodesty.

"With the power of our scandalous bodies combined, we should surely produce an earthquake.

"If not, I'm sure Sedighi can come up with a rational explanation for why the ground didn't rumble."

And you can now make that number 21,000 - and rising fast.

Q&A with Boobquake founder Jennifer McCreight