The mountain "has exploded already", the head of the Merapi section at the Center of Vulcanological Research and Technology in Yogyakarta told Reuters.

He cautioned, however, that the mountain's eruption process could be gradual rather than a sudden burst.

From Ketep, the top of Merapi was totally obscured by thick gray and white clouds, which trailed down the volcano's slopes.

Earlier, Ratmono Purbo, the head of the vulcanology center in Yogyakarta near the volcano, told reporters the mountain was spewing clouds of hot gas and was raining down ash.

Neither are new since activity picked up in recent weeks on Merapai, one of the most menacing volcanoes in the Pacific "Ring of Fire", and there have been several lava flows in past days.

But Purbo said of Monday's hot clouds: "This is the biggest pile we have so far, adding that they "are billowing out of the crater for four kilometers (2.5 miles)".

Indonesia raised on Saturday the alert status of Merapi to the highest level, also known as code red or danger status, although experts said they could not predict when it would erupt.

They have described the mountain as being in an "eruption phase" for weeks, but are looking for a substantial amount of volcanic material to be ejected straight into the sky to a substantial height to qualify it as a full eruption.

The top alert level for the mountain means residents can be forced to evacuate. Authorities moved more than 5,000 people living near the volcano to shelters in safe areas after the new alert level.

Thousands more moved earlier, but some have refused to leave their homes while others have continued to return during the days to tend livestock, collect grass, or otherwise carry on their daily routines.

Indonesian media reports said many who previously held back were leaving on Monday, carried in hundreds of trucks and cars.

Some residents would rather rely on natural signs than official orders.

They say those signals would include lightning around the mountain's peak or animals moving down its slopes.

Officials put the total number of residents on and near the mountain at around 14,000.

There were no immediate reports of injury or damage from the moderate quake, which struck at 5.32am local time (17h32 GMT on Sunday).

The tremblor was centred 40km north-west of the capital and 60km below the earth's surface, GNS Science, the nation's geological agency, said in a statement.

The earthquake was felt throughout the Wellington region.

New Zealand sits above an area of the earth's crust where two tectonic plates are colliding and records more than 14 000 earthquakes a year - but only about 150 are felt by residents.

Chanchu was tracking west-northwest towards the South China Sea and was expected to have moved on by Sunday morning, the state weather bureau said.

In the worst accident during the storm, motorboat Mae Ann 5 capsized just off the central city of Masbate Friday.

Officials are unsure how many passengers were aboard, but coast guard spokesman Lieutenant Commander Joseph Coyme said 21 bodies had been fished out of the water.

"As of the report we got before 12 noon, there were 21 dead bodies recovered and 18 survivors," Coyme told AFP.

"Our operations will be continuing for the rest of the day, and we advise fishermen and ferries in affected areas not to venture out to sea because of huge waves," Coyme said.

Masbate remains "isolated considering that there is no electricity and there is no communication in the province as of now," said provincial police chief Senior Superintendent Eugenio Alcuvindas.

A second ferry, which was docked at a port in Albay province, sank, but there were no reports of casualties.

Coyme said another missing ferry with over 700 passengers on board had been located after hours of searching rough seas.

Two tugboats were dispatched to help the Filipinas Princess, which was reported missing at the height of the storm Friday night but was found anchored in a cove near Mindoro island south of Manila.

"The vessel took shelter in a cove because of high winds and waves. We are in contact with them and tugboats have been sent to rescue them," Coyme said.

The civil defense office said over 23,000 people in the eastern and central regions have been evacuated, while nearly 8,000 people were stranded in major ports after the coast guard suspended sea travel.

Heavy rains and strong winds were continuing to pound several provinces Saturday in the main island of Luzon. Power, which had been down in many areas, had been partly restored as of Saturday, it said.

Fallen trees and debris blown by the wind also littered some streets in Manila and in nearby suburbs.

Large suburban areas near Manila were also without electricity after trees and fallen billboards toppled lines, the Manila Electric Co. said adding that repairs were being rushed and services should resume later in the day.

Chanchu was packing maximum sustained winds of 95 kilometers (58 miles) per hour near the center with gusts up to 120 kilometers per hour, the weather bureau said.

Its chief, Graciano Yumul, said Manila and nearby provinces, as well as the island of Marinduque to the south, would continue to experience strong winds and rain. Storm warnings in some other areas were lowered.

"It is heading towards the South China Sea and by theory the weather should be better once that happens," Yumul told DZMM radio.

"But we are monitoring this because once it exits to the South China Sea it would intensify and there is a danger it could make a U-turn back to the Philippines," he said.

About 100 residents were evacuated from their homes in Wakefield because of concerns about two dams in the area, the state Office of Emergency Management said. At least a dozen dams were being closely watched.

Officials also reported a railroad culvert and embankment washed out in Milton, with train tracks suspended in midair. And the local emergency management office in Hooksett said the town essentially was closed because so many roads were flooded.

Tom Johnson said water was flowing on Sunday into the basement of his Salem home, where a pump that handles 1,500 gallons of water an hour was not keeping up.

"There are areas in my backyard that are probably 3 feet deep and climbing as we speak," Johnson said.

In Maine, flooding was reported on 60 roads in the southern part of the state, said governor's spokeswoman Crystal Canney. Shelters were set up in Kennebunk and Ogunquit.

Massachusetts Gov. Mitt Romney declared a state of emergency on Sunday, activating the National Guard and various state services to help communities respond to the storm.

Boston had picked up 4.35 inches of rain in 24 hours. Farther north, Newburyport collected 5.83 inches over the same period, according to the
National Weather Service.

Flooding in New Hampshire in October killed seven people, carried off homes and washed away miles of roads down to bedrock.

The woman's body had been in the water for about three days, authorities said.

She suffered animal bites that were consistent with an alligator, which "did play some part in the victim's death", according to a preliminary autopsy. The cause of death was pending and the medical examiner's final report will not be released for at least four weeks, the sheriff's office said.

"We don't know the condition she was in when this happened," said state wildlife spokesman Gary Morse.

Authorities were baiting traps in their searches for both alligators Sunday.

On Wednesday, construction workers found the dismembered body of a Florida Atlantic University student in a canal near Fort Lauderdale. A medical examiner concluded that the 28-year-old woman was attacked near the canal bank and dragged into the water.

On Saturday, wildlife officers captured a ten-foot alligator in Sunrise that they believe fatally attacked Yovy Suarez Jimenez while she was out jogging.

Suarez's death was the 18th confirmed fatal alligator attack in Florida since 1948. Nine other deaths are unconfirmed, mainly because it was not clear whether the person was already dead when the alligator attacked.

What provoked the attacks in three separate Florida counties was unknown, but state wildlife officials said alligators are generally on the move looking for mates and food this time of year.

"As the weather heats up, the alligators' metabolism increases and they have to eat more," Florida Fish & Wildlife Conservation Commission spokesman Willie Puz said Sunday. "They might be moving more, but that just shouldn't mean increased alligator attacks."

Florida residents are warned not to swim in heavily vegetated areas, feed wildlife or walk pets near the water, especially between dusk and dawn when gators are more active, Morse said.

"There are some things that can cause alligators to associate people with feeding opportunities," Morse said.

A direct hit on an urban area could unleash more destruction than Hurricane Katrina, the 2004 Asian tsunami and the 1906 San Francisco earthquake combined. The blast would equal 880 million tons of TNT or 65,000 times the power of the atomic bomb dropped on Hiroshima.

Objects this size are thought to hit Earth about once every 1,000 years, and, according to recent estimates, the risk of dying from a renegade space rock is comparable to the hazards posed by tornadoes and snakebites. Those kind of statistics have moved the once-far-fetched topic of killer asteroids from Hollywood movie sets to the halls of Congress.

"Certainly we had a major credibility problem at the beginning - a giggle factor," said David Morrison, an astrobiologist at NASA's Ames Research Center in Mountain View, Calif. "Now, many people are aware this is something we can actually deal with, mitigate and defend against."

In 1998, lawmakers formally directed NASA to identify by 2008 at least 90 percent of the asteroids more than a kilometer (0.6 mile) wide that orbit the sun and periodically cross Earth's path. That search is now more than three-quarters complete.

Last year, Congress directed the space agency to come up with options for deflecting potential threats. Ideas seriously discussed include lasers on the moon, futuristic "gravity tractors," spacecraft that ram incoming objects and Hollywood's old standby, nuclear weapons.

To help explore possible alternatives, former Apollo astronaut Rusty Schweickart has formed the B612 Foundation. The organization's goal is to be able to significantly alter the orbit of an asteroid in a controlled manner by 2015.

"You can watch all of the golf on television you want, but if you want to go out and break par, it's going to take a lot of playing," Schweickart said. "And you're going to learn a lot that you thought you knew, but you didn't."

Throughout their 4.5 billion-year history, Earth and its neighboring planets have been like sitting ducks in a cosmic shooting gallery.

A glance at our moon shows the scars left by countless collisions with asteroids and comets. In fact, the moon is thought to have been created when part of the early Earth was ripped away in a cosmic impact with an object the size of Mars.

Earth also has scars, but most have been hidden by vegetation or eroded by geologic processes such as rain and wind. About 170 major impact sites, including northern Arizona's 4,000-foot-wide Barringer Crater, have been identified around the globe.

Within the past century, an extraterrestrial chunk of rock about 200 feet wide is thought to have caused a 1908 blast near Tunguska, Siberia, that leveled 60 million trees in an area the size of Rhode Island. Researchers theorize the object exploded four to six miles above the ground with the force of 10 million to 15 million tons of TNT.

Few outside scientific circles took the threat posed by near-Earth objects seriously until 1980. Then, Luis and Walter Alvarez published a study based on geologic evidence that concluded a cataclysmic asteroid or comet impact 65 million years ago caused the mass extinction of two-thirds of all plant and animal life on Earth - including the dinosaurs.

Dubbed the Great Exterminator, the colossal object was estimated at 7 miles in diameter and created a blast hundreds of millions of times more destructive than a nuclear weapon. Objects that size are thought to hit Earth about every 100 million years.

NASA scientists studying satellite photos bolstered the Alvarezes' theory with the discovery in 1991 of an impact crater 125 miles wide buried beneath the northwestern corner of Mexico's Yucatan Peninsula. Three years later, NASA photos of another sort drove home the potential for cosmic collisions in our part of the solar system.

Spectacular images from the Hubble Space Telescope of Comet Shoemaker-Levy's collision with Jupiter showed 21 comet fragments, some more than a mile wide, producing colossal fireballs that rose above the giant planet's cloud deck.

"I think the most important development for getting this (public awareness) going was the Alvarezes' research that the dinosaurs went extinct as the result of an impact," Morrison said. "We were faced with a real example where an impact had done terrible damage."

In 1998, a year in which the asteroid-disaster flick Armageddon was the top-grossing movie worldwide, Congress held hearings that led to the creation of a Near Earth Object Program office at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

That year marked the beginning of the Spaceguard Survey aimed at discovering 90 percent of near-Earth asteroids more than a kilometer wide.

Today, astronomers at five primary U.S. sites work on the survey, which NASA funds with about $4 million annually. Scientists estimate there are 1,100 near-Earth asteroids that are larger than a kilometer wide. With two years to go, they have found 834, or about 76 percent, of the estimated total.

Congress directed NASA in December to look at expanding the search to asteroids larger than 140 meters (460 feet) in diameter and completing the new survey by 2020. Objects that size are capable of destroying a city.

The more often an asteroid or comet is sighted, the more precisely its orbit can be calculated. Researchers hope that radar observations of Apophis taken last weekend by the Arecibo telescope in Puerto Rico could make the odds of a collision even more remote.

"I always use the analogy of a hurricane," said Don Yeomans, manager of the Near Earth Object Program. "When it first forms in the Caribbean, you have no idea where it's going to hit. If you continue to track the hurricane over days and weeks, the future path becomes more predictable."

That uncertainty led former astronaut Schweickart to send a letter to NASA Administrator Michael Griffin last June proposing to land a radio transponder on Apophis to better track its course. For now, the space agency plans to simply monitor the asteroid during passes this year and in 2013.

In 2029, seven years before the possible impact, the asteroid will come closer to our planet than the television and weather satellites that beam back signals from 22,300 miles above. Astronomers' big fear is that Apophis will pass through a gravitational "keyhole" that will put it on a collision course with Earth in 2036. "For all practical purposes, it (a mission) would have to be done before the 2029 flyby to take advantage of the leverage afforded by that encounter," said Steve Chesley, an astronomer in the Near Earth Object Program. "That means the 2036 impact needs to be addressed by 2026, 10 years earlier."

There is considerable debate about how to stop an asteroid or comet once astronomers have determined it will pass too close for comfort.

One idea would use a laser cannon on the moon or atop a spacecraft to shift the threatening object's course. Another involves slamming a spaceship into the object to nudge it away. A slight push a decade or so before a possible collision would translate into a wide miss years later.

Astronauts Ed Lu and Stanley Love published an idea last year for a "gravitational tractor" to change an asteroid's orbit. A nuclear-powered spacecraft would be launched toward the rock and hover near it, using gravity to slowly divert the intruder.

A fallback option using readily available technology involves detonating a nuclear weapon near the threat to shove it off course. It might be the only alternative if an object is discovered only a few months before impact.

Most experts agree the response will depend on the specific threat.

"You have to discover and know your enemy before you can even imagine what kind of mission or deflection you would do," Morrison said.

In recent months, some of the larger political questions are starting to be widely discussed.

If the Earth is threatened, NASA almost certainly would help lead the response. But who ultimately makes the decision on how to proceed? The United States? The United Nations? What about cases where deflecting an object away from an endangered region might move its course across another area? And how likely does a threat have to be to warrant taking action?

Schweickart is convinced those sorts of decisions should be made by the entire planet. He has begun work on a draft treaty he hopes to present to the United Nations by 2009.

As for Apophis, NASA scientists are confident the knowledge they've gained will prevent the asteroid from becoming the next cosmic catastrophe.

"Apophis is not going to hit the Earth. Period," Chesley said. "Whatever the impact probabilities that we compute right now are, we're not going to let it."