So much for that false sense of security.

The rash of disastrous earthquakes in Turkey, Greece, Taiwan and just last week in Mexico has brought back some scary memories for countless Angelenos but more important, it’s prompting the inevitable questions about the inevitable day when L.A., too, will be shaking.

How much damage would there be?

How many deaths?

Who would pay to rebuild?

What on earth are we doing here?

There is no shortage of unnerving scenarios that involve buckling sidewalks, swaying skyscrapers and screaming pedestrians. But in the wake of the major quakes around the world, Los Angeles can take a certain degree of comfort.

While damage from a Northridge-type shaker could approach $100 billion perhaps even higher, depending on where it’s centered and while some tall buildings might very well topple, there’s a pretty good chance of surviving to tell about it.

“In terms of saving life and limb, we’re better prepared than almost any other metropolitan area in the world,” said Paul Flores, vice president of EQE International, an engineering and risk assessment firm.

That’s because the region is so heavily developed over such a massive area, much more so than other quake-vulnerable areas around the world. “Our codes are focused on preventing fatalities; the buzzword is ‘build to life-safety,’ ” said Kimberley Shoaf, research director for the Center for Public Health and Disaster Relief at UCLA.

Many of those structural safeguards have been improved upon since the 1994 Northridge temblor.

“Because of the prevention actions that have already been taken, we don’t expect to see a Taiwan or Turkey in Los Angeles,” said Jane Bullock, chief of staff for the Federal Emergency Management Agency. “The building codes are better and there is much better enforcement.”

Among the improvements in recent years:

? Retrofitting of thousands of commercial and residential structures throughout Los Angeles County;

? Billions of dollars in regional infrastructure upgrades;

? Refinements to emergency-response plans;

? Identification of several previously unknown faults.

It’s not all good news, of course. Los Angeles remains vulnerable to quake-related death and destruction on a number of fronts. “I’m worried that (the improvements) might make us complacent,” said Shoaf. “A lot of the injuries and damage we see in quakes are absolutely preventable, even in Northridge. We have to also look at injury and economic risk.”

Among the points of vulnerability: Untold numbers of unreinforced masonry buildings; thousands of concrete buildings; apartment buildings situated atop parking garages; structures on landslide-prone areas, steel-frame highrises with faulty welds, and areas with high water tables.

Unraveling the mystery

Of course, no one really knows what would happen. There are just too many variables. There always are. The 6.7 Northridge quake actually resulted in fewer casualties than what many experts had been expecting.

“We have quite a bit of experience with moderate earthquakes, in the 6.0 to 7.0 range, and we know how to prepare for those, but we don’t have the experience of going through a really big earthquake,” said Tom Heaton, a seismological engineer at Caltech. “There’s a lot we don’t know about how things would turn out in such a quake.”

It is that dearth of information that prompted a number of prominent local scientists to travel overseas and examine the damage from the massive quakes in Turkey and Taiwan. The hope is that by seeing which buildings and roads were most damaged and how current building codes in those countries withstood the tests, the lessons can then be applied to Los Angeles.

There are plenty of risks and vulnerabilities that experts already are knowledgeable about the locations of major faults, the types of soils that intensify shaking, the sorts of buildings most prone to collapse, the ways in which certain structures will sway, and more. Elaborate plans are in place with respect to emergency response and even rebuilding from a massive quake.

Even so, “when you get a quake of major magnitude in an urban area with lots of older buildings, it’s very tough to prepare for it,” said L.A. City Councilman Hal Bernson, who represents the district in which the Northridge quake was centered.

Some fault basics

There are two types of quake locations that could wreak tremendous damage: a great quake (magnitude 7.8 or higher) on the San Andreas Fault which at its closest point is 75 miles from downtown L.A.; or a quake at least as large as Northridge on a fault within the basin.

While the San Andreas is the most well-known, several faults can produce substantial quakes of their own, including the Newport-Inglewood Fault (capable of producing a 7.3 quake), the Whittier Fault, the Santa Monica Fault and the Elysian Park Fault directly underneath downtown.

“Remember, the Northridge quake took place on a fault that was previously unknown,” said Bob Canfield, chief administrative analyst for the emergency preparedness division for the city of Los Angeles.

Just this year, scientists discovered another fault, the Puente Hills Fault, running from the downtown area toward the southeast.

But as was evident from Northridge, the extent and location of damage depends on more than where the epicenter happens to be. The types of soils and buildings are significant factors.

Most of the 8,500 or so un-reinforced masonry buildings in L.A. have been overhauled since the city made such retrofitting mandatory in 1981. And in 1996, the Council passed another mandatory retrofit ordinance for the 2,500 or so concrete tilt-up buildings built before 1976. But other localities have not made such requirements.

It’s not hard to come across weak links. Following the Northridge quake, it was discovered that the welds used in many of L.A.’s skyscrapers were faulty. Some of them have been fixed, but the fear is that in a major quake centered closer to downtown, enough could fail to cause some skyscrapers to collapse.

Concrete buildings with inadequate steel rebar reinforcement primarily those built before the mid-1970s also could sustain major damage, according to Heaton of Caltech. Yet there is no requirement that they be further reinforced. Local building and safety officials say they recognize the threat, but have not been able to convince the City Council to require retrofitting.

“We’re trying to make it mandatory, but it just hasn’t happened yet,” said Bob Steinbach, spokesman for the L.A. Department of Building and Safety. He said the department is drafting an ordinance and has even sent a team to Taiwan to see how similar buildings fared.

Economic concerns

Bernson said he would introduce the ordinance as soon as Building and Safety finalizes the provisions. But the councilman conceded that getting such an ordinance approved will not be easy. “Each of these ordinances carries with them tremendous economic impacts that the council members are all too aware of,” he said.

That’s especially true of older apartment buildings, which face some of the greatest risks. Owners of many such buildings are finding it hard enough just to meet basic health and safety standards, let alone pouring millions into retrofitting buildings that are several decades old.

“Multifamily homes are the most vulnerable building stock in L.A. right now,” said Bullock of FEMA. “We can’t predict what the damages will be.”

As for the region’s infrastructure the roads, bridges, power and water systems and gas lines most experts agree that significant strides have been made. Since the 1989 Loma Prieta quake in the Bay Area, the California Department of Transportation has retrofitted almost all of the highway bridges and overpasses in the state at a cost of about $4 billion.

Only a few toll bridges including the Vincent Thomas Bridge in the Harbor area remain to be retrofitted, according to Caltrans spokesman Jim Drego.

But some of the welds used in the reconstruction of two interchanges the Golden State (5) and Antelope Valley (14) freeways in Santa Clarita and the “Orange Crush” interchange of the 5, 57 and 22 freeways in the Anaheim/Santa Ana area failed in shaking tests and are now being replaced.

Fire threat

In addition, only a small fraction of homes and businesses have gas-shutoff valves, according to Charles Scawthorn, an analyst at EQE International. “There has been a very slow deployment of these shutoff valves, and there is no reason for it, since they’ve been around for more than 10 years,” he said.

Water system breakdowns were a short-term problem during Northridge and could be an even bigger problem in a larger quake, Scawthorn added.

Both of these problems could contribute to the spread of fires. “This is a huge concern,” said Scawthorn. “If you have hundreds or thousands of simultaneous ignitions, and then you throw in poor communications, poor road conditions, interruptions in water supplies, it’s going to be very hard to fight these fires, even for a fire service as excellent as the one L.A. has.”

The damage from these fires, he said, could easily top $10 billion dollars.

Other emergency response systems could be strained, too. Getting to thousands of people trapped inside collapsed structures, tending to the hundred thousand or more people with injuries, and providing emergency rations and shelter for those whose homes are damaged, will be formidable tasks.

UCLA’s Shoaf said the emergency response would be most severely strained in a great quake on the San Andreas Fault, because the damage would be so widespread.

“A 7.0 quake on the Newport-Inglewood Fault would primarily affect the Westside, the Valley and Orange County; you could still mobilize services and supplies in adjacent areas and move them in quickly,” she said. “But an 8.0 quake on the San Andreas would affect the entire regional infrastructure; there might not be any adjacent staging areas because they would all be damaged.”

Even organizations like the Red Cross, which is expert at moving supplies into devastated areas, would have problems.

“In a catastrophic quake, when there would be hundreds of thousands of people needing help, we wouldn’t be able to take care of everyone for the first few days,” said Peggy Brutsche, director of disaster services for the Greater Los Angeles Chapter of the Red Cross.