LOS ANGELES (Reuters) - After almost a decade in which torture films dominated the box office, horror movies are returning to ghostly thrills with a new slew of low-budget productions making big money for studios.

The success of 2009's "Paranormal Activity" - which was made for $15,000 and grossed more than $107 million at U.S. box offices - has fueled a thirst in audiences and movie studios for things that go bump in the night.

Halloween audiences previously gripped by the gory "Saw" franchise about a sadistic serial killer are flocking this season to see supernatural horrors, with "Sinister" and "Paranormal Activity 4" providing otherworldly scares for the spooky festivities.

The supernatural trend, with very little blood, started this year with "The Woman in Black" and "The Apparition", and will spill into 2013 with upcoming horror films including "Mama", "Evil Dead", "Carrie", and ghostly spoof "Scary Movie 5", which will parody "Paranormal Activity".

"It's a return to a more classic style of suspense," Henry Joost, who co-directed the third and fourth "Paranormal Activity" films with Ariel Schulman, told Reuters.

"When you've just been obliterated with gore, having it slammed in your face for a decade, you respond by seeking the opposite."

"Sinister", currently playing in U.S. movie theaters for Halloween-loving audiences, features an author (Ethan Hawke) who discovers home videos of mysterious murders and soon finds himself pursued by an otherworldly presence.

Director Scott Derrickson said audiences were drawn to bloodless supernatural horrors as a means to escape from news about wars and violent killings.

"There's something about the real-world pain and violence that has enveloped the American reality, that makes films like ("Saw") not necessarily the catharsis that people are looking for," Derrickson told Reuters in an interview.

INEXPENSIVE GHOSTS REAP BOX-OFFICE BENEFITS

"Saw", made for $1.2 million, grossed more than $55 million at the U.S. box office in 2004 and spawned a franchise, leading a slew of films dubbed "torture porn" for the excessive use of gratuitous violence.

The trend produced the "Hostel" trilogy, 2006's "The Texas Chainsaw Massacre: The Beginning" and 2008's "The Strangers".

But while the "Saw" franchise initially brought in big money for movie studios - the second and third films each grossed more than $80 million at the domestic box office - the profits slowed by 2009, when the franchise's seventh and final film "Saw 3D: The Final Chapter" was made for $20 million and grossed only $45 million.

"The torture porn stuff really played itself out, 'Saw' and 'Hostel', they were just too much. People want to be engaged with the story and not just grossed beyond imagination," Bradley Jacobs, film editor at Us Weekly, told Reuters.

In comparison, the "Paranormal Activity" franchise, which relies on suspense and strange phenomena, has revamped the genre with a more cost-effective model since most of the scares are off-screen and on deliberately grainy footage, minimizing the need for costly special effects and action shots.

The second "Paranormal" film was shot for an estimated $3 million and made $84 million, while the third film, made for $5 million, has grossed more than $104 million in North America.

"The profitability of making a film for less than $5 million and hedging the bet of the financiers and the studios with a possible giant upside becomes extremely attractive," Derrickson said.

"Sinister", made for $3 million, has grossed $39 million after three weeks in U.S. theaters. "Paranormal Activity 4", which cost $5 million, has made more than $42 million since it opened on October 19.

"Audiences realized that the feeling of suspense and the anticipation of horror is actually more emotionally impacting than graphic horror itself in these low-budget movies," Derrickson said.

The "Paranormal Activity" franchise was released by Paramount Pictures, a unit of Viacom Inc, while Lions Gate Entertainment's Summit studio distributed "Sinister" as well as the "Saw" and "Hostel" films.