San Francisco - Breasts were big on Facebook on Monday as a female blogger called on women to prove wrong an Iranian cleric who preached that cleavage causes earthquakes.

As a cyber-organised event dubbed "Boobquake" got underway, a temblor measuring 6.5 on the Richter scale hit Taiwan prompting playful online banter about whether there was merit to the cleric's contention.

More than 55 000 people were backing the official "Boobquake" page of Jennifer McCreight, a self-described "geeky, perverted atheist feminist" putting her D-cup breasts where her mouth is.

"No, the Taiwan earthquake is not statistically significant - yet," the college senior said in an update to her blog.

"If we get many of a similar magnitude in the next 24 hours, then we might start worshiping the power of immodesty."

'Leading men astray'

McCreight, who lives in the US state of Indiana, used the world's leading social network and microblogging service Twitter to enlist women worldwide to test the cleric's assertion that sexy women can make the ground shake.

"Many women who do not dress modestly... lead young men astray, corrupting their chastity and spread adultery in society, which (consequently) increases earthquakes," Hojatoleslam Kazem Sedighi was quoted last week as saying by Iranian media.

What started as a barbed poke at what she saw as bad science on the cleric's part won a passionate following as it bounced around the internet, and by Monday a pair of Boobquake rallies were planned.

Online shop Zazzle.com embraced the movement, selling "Boobquake 2010" t-shirts with pink ribbon designs. Money made from selling the shirts will go towards the fight against breast cancer.

"Who can resist the opportunity to show cleavage for a good cause?" a Twitter user with the screen name MBodman 88 asked rhetorically in a tweet. "Really, everybody wins today."

Natural causes

McCreight chose a titillating low-cut red blouse with spaghetti string straps for the day, posting a photo of herself at her blog online at blaghag.com.

She rejected the notion that accentuating her breasts caused an earthquake in Taiwan, saying she would only consider taking credit for temblors in her time zone. She pointed out that there are known natural causes for earthquakes.

"I encourage other female sceptics to join me and embrace the supposed supernatural power of their breasts," McCreight said on the Boobquake Facebook page.

"Or short shorts, if that's your preferred form of immodesty."

While the Boobquake rallies were lightly attended, messages flooding Twitter and Facebook indicated that women were planning to slip on skimpier or tighter tops in solidarity with the message to keep science and sexuality separate.

A blogger at Iran.com invited about 100 men and women friends to take part in Boobquake as a provocative way to advocate support of science.

"I can just have a good laugh," Azarin Sadegh wrote at Iran.com.

"But for the women living in Iran, it is not a joke. This is just the red flag, the starting whistle for the Basij and Hejab patrols to go after them.