Monday, March 27, 2006

All Shook Up

All Shook Up

Earthquakes really scare me. Admittedly, I've never been anywhere that experienced a big one, but I have to wonder if the City of St. Louis really is prepared for one of a significant magnitude.

The midwest has frequent seismic activity. Most of it is pretty small stuff that you can't even feel unless you're really close by and it's really close to the surface. As recently as November 22, 2005, there was an 2.5 tremor with an epicenter at approximately N. 40th St. and Waverly Ave. in the Lansdowne neighborhood of East St. Louis.

According to the 'earthquakes' layer on Google Earth, a 3.0 magnitude shaker occurred in St Marcus Commemorative Park off Gravois in South St. Louis, on September 20, 1978. That might be the only one with an epicenter inside the city limits in recent memory.

SLU reports on a bunch of historical quakes felt in St. Louis. I think I recall feeling the one on February 5, 1994, although its epicenter was near Cape Girardeau.

Our historic brick housing stock with rubble stone foundations is wonderful, but also potentially dangerous in a 'quake. And the cavey Karst topography in parts of the region doesn't help matters.

If St. Louis does experience a severe earthquake, the aftermath will be the biggest concern. We managed to cope reasonably well, in some ways, after the flood of 1993.

But its arrival was long anticipated, and its effects were concentrated in certaiin areas of the region. The flood plains along the Missouri, Mississippi, River des Peres, and a few other tributaries were damaged the most. Some other areas did experience sewer backups. Concrete, immediate attempts to prevent the damage were made, like sandbagging and shoring up levees.

A significant earthquake would have widespread impacts. I know MODOT has spent years and millions of dollars to retrofit Highway 40 in downtown to prevent another tragedy like what happened on the Nimitz Freeway in Oakland on October 17, 1989.

Apparently, I-44, I-70 and Route 100 (Manchester, in the County anyway) are designated as Earthquake Emergency Highway Routes. Also, any new bridge or overpass built since 1990 by MODOT should meet seismic design standards.

But that still seems to leave a number of places vulnerable. For example, what about the double-decked stretch of Highway 40 from about Forest Park Parkway/Compton/Market to west of Vandeventer? That section spans Grand Boulevard, a major north-south thoroughfare. If it isn't retrofitted, that seems like a huge potential problem. Likewise, although the Grand viaduct across MetroLink and the railyards just south of there is scheduled for reconstruction soon, Grand itself passes above Eastbound I-64 and below Westbound I-64 on a 1940s structure built as part of the Market Street bypass.

I know some work has been ongoing in that area; and the Compton and Market bridges are scheduled for replacement this year. (That'll be a huge traffic mess, no doubt, as Market, Compton, and Forest Park traffic will need to detour via Olive, Jefferson, and Chouteau.)

Then there's the bridges and overpasses maintained by the City's BPS. They've been more aggressive lately about planning and scheduling bridge replacements; for example, Lansdowne over River des Peres was finished pretty fast, and now the small Arsenal bridge next to Schnucks as well as the South Broadway bridge over River des Peres are being replaced currently. Still, there are a number of bridges built during the 1970s and 1980s - for example, the Vandeventer/Tower Grove viaduct spanning the railyards - that I suspect are not seismic-compliant.

Then there's that awful South Kingshighway viaduct over the UP track between Southwest and Shaw. It really needs to be replaced soon, although I realize it would be a real traffic nightmare to detour to Vandeventer. At least Vandeventer now has full direct I-44 access (unlike Kingshighway).

And we probably shouldn't even think about the bridges owned by the railroads themselves. A couple years back, the BNSF trestle over Watson Road between Mackenzie Pointe Plaza and Kenrick Plaza in Shrewsbury collapsed. All they seemed to do to reinforce it was put in more rocks. Similarly, there's a UP trestle over South Kingshighway between Fyler and Home Depot that's supported mainly by fill dirt.

A major earthquake in St. Louis would be at least as destructive as Hurricane Katrina was in New Orleans. Are we doing enough to prepare?

3 comments:

Michael M. said...

We are nearly an island. Is it possible to enter or exit without crossing a bridge?

barbara said...

I read somewhere that Manchester Road of all things (it takes on some single-letter designation out in the exurbs) is the only "major roadway" that will take one out of the City/County area without crossing any river. If that's not something to keep you lying awake at night, I'm not sure what is!

Michael M. said...

From what I can see, you are right about Manchester. It does go over 270, though, and it crosses some small stream at Hanley.