Ship Creek development leaves some worrying: What if there's an earthquake?

When the Alaska Railroad Corp. and a developer announced plans last month to build a residential complex in Anchorage's industrial Ship Creek neighborhood, some questioned what would happen to the land — and the proposed development — in the event of a significant earthquake.

Downtown Edge will be home to 28 townhouse-style condos at the corner of Christensen Drive and West Second Avenue, on land owned by the Alaska Railroad Corp., as part of a larger development called The Rail. The area lies in seismic zones 4 and 5, categories designated by the city that indicate a high or very high susceptibility to ground failure in an earthquake.

A seismic hazard zone 5 area is a "region for which the largest potential displacements are predicted," according to a city risk assessment from 2013. It's also the category that includes "areas of previous seismically induced landslides."

Buzz Scher, a commissioner on the city's Geotechnical Advisory Commission, said the area where Downtown Edge is planned "appears to be" a landslide that moved into place sometime prior to the magnitude-9.2 earthquake in 1964 that forever changed the topography of Southcentral Alaska.

But, Scher said, "as best as any existing information can tell, it did not move in the (1964) earthquake."

[7.1 quake in 2016 shook different parts of Anchorage in very different ways]

The railroad had tried courting commercial tenants to develop on the land where the condos are planned.

"We've owned it for over 10 years and we haven't had any luck getting anyone (commercial) to build anything new there," said Jim Kubitz, vice president of corporate planning and real estate at the Alaska Railroad. "We realized the value of it isn't in commercial, it's in residential."

Residential is cheaper to build per square foot downtown, he said. That's because residential projects are generally smaller than commercial and therefore don't require the same earthquake-related reinforcement measures, such as pilings for added support.

Later, the plan is to bring commercial tenants to part of The Rail in an area that's flat and lower-lying than Downtown Edge. The residential development will partly be terraced on a slope overlooking the railroad and Cook Inlet.

Large hotel and office spaces shouldn't be built in zone 4 and 5 areas, according to recommendations in the 2013 city assessment, and certain kinds of multifamily residences built on shallow foundations shouldn't be built in the highest-risk areas.

"There are differences of opinion," said Scher, who is also a member of the Alaska Seismic Hazards Safety Commission. "I am on one side that is that there should be a very narrow band of what should be allowed in seismic zone 5. Those are usually the areas that have failed in the past. To me those kind of areas are great for parks or parking structures but I don't think we have business putting people in there. … Going into anything, when any project comes to us, that's where I start from."

In the announcement about Downtown Edge, Anchorage Mayor Ethan Berkowitz mentioned the need for new housing downtown. A 2014 Anchorage Economic Development Corp. survey of more than 600 workers in the city found that downtown was the No. 1 area where people wanted to live, followed by Turnagain, South Anchorage and the lower Hillside.

Building in areas most at risk during an earthquake isn't new for Anchorage. Parts of the city's Turnagain neighborhood have been developed since the massive 1964 Alaska earthquake, sometimes "atop the ruins of old houses" that were wrecked, Alaska Dispatch News reported in 2014.

Many buildings in and around downtown Anchorage already exist in zones 4 and 5, including in South Addition and much of Third, Fourth and Fifth avenues roughly west of Ingra Street.

The 1964 quake resulted in land in downtown Anchorage undergoing "significant movement," according to the city's risk assessment.

"Earthquakes are considered (when building)," Scher said. "It's part of the process, and it's very important. … The muni takes the hazard very seriously."

A report from architectural firm KlingStubbins in 2014 said that proposed development in the Ship Creek area would need further analysis of seismic and soil characteristics. The city hired KlingStubbins in 2013 as part of its effort to re-envision the future of the entire Ship Creek area.

Trevor Edmondson is the vice president and general manager of the Petersen Group, the builder for Downtown Edge. He said in an email that the project will be built to Anchorage standards that take into account the "geotechnical conditions of the site" but didn't offer specifics when asked about any concerns the group might have for how an earthquake might affect the project.

[In aftermath of giant quake, Anchorage allowed rebuilding in slide-prone Turnagain area]

The project still needs to go before the city's Geotechnical Advisory Commission, where it will be heard on Feb. 28, but it doesn't require the commission's approval to move forward. The development will need approval from the Anchorage Assembly.

"Buildings in these locations (or any location, for that matter) go through rigorous permitting and plan review prior to approval for construction or occupancy," said Chris Schutte, director of the city's Office of Economic and Community Development, in an email.

"It's one of those things where there's a certain amount of risk involved developing anywhere," said Kyle Brennan, chair of the geotechnical commission. "This site, it's probably not the best place to build residential structures. … I'm not saying it's totally off limits, but at the same time, we want to see a little more information so we can kind of decide whether we think it's a good idea."

When it comes to seismic risks in the area planned for the Downtown Edge development, Kubitz, with the Alaska Railroad, said: "I think everyone has a concern about that. … I know they're going to do whatever is allowable, and I'm sure not any more than that."