By David Noss
CALIFORNIA, Md. (August 24, 2011)—Since yesterday's 5.8 earthquake centered northwest of Richmond—approximately 80 miles from Lexington Park as the crow flies—there have been 3 aftershocks: a 2.8 at 2:46 p.m., a 4.2 at 8:04 p.m., and a 3.4 at 12:45 a.m. The initial quake was felt as far north as Ontario Province in Canada.
The magnitude reported by USGS refers to the Richter magnitude scale. The Richter scale is logarithmic. A 5.0 quake has a shaking amplitude 10 times larger than one that measures 4.0.
Large bridges have been inspected
Both the Harry Nice Bridge, that spans Charles Co. into Virginia, and the Thomas Johnson bridge, that spans Calvert County into St. Mary's, have undergone inspections.
The Nice bridge was first closed right after the quake from approximately 1:55 p.m. to 4:40 p.m. to allow for inspection. The MTA says the bridge was closed as a "precautionary measure." County officials announced later in the evening that the bridge was being closed again for inspection at 7:30 p.m. The bridge was reopened at 7:45 p.m.
The Calvert County Sheriff, after the quake, announced that there were no plans to close the Thomas Johnson bridge. Later that evening around 7:30 p.m., they announced that the bridge would be one lane traffic between 9 a.m. and 12 p.m. on Wednesday to allow for inspection. Wednesday morning, SHA
changed the inspection time to between 10 a.m. and 3 p.m.
Two structural engineers will inspect the bridge using a large crane with a bucket on an arm that extends over the side and under the bridge. The snooper truck must be parked in a lane on top of the bridge and allow safe, hands-on and visual inspection underneath.
There has been no public statement regarding the status of the inspection
as of publication time. Constructed in 1977, the Thomas Johnson Bridge carries more than 28,000 vehicles each day.
Across the state, MTA reports that their engineers continue proactive inspection of bridges, prioritizing larger and taller structures. SHA has not received any reports of damage. Additionally, maintenance crews inspected roads across the state, looking for any unusual bumps or depressions on SHA road surfaces. Crews have also visually inspected traffic signal poles, light poles, overhead sign structures and utilities with no damage reported.
SHA owns and maintains more than 2,500 bridges and 17,000 miles of highways. We are being conservative and proactive to confirm the integrity and safety of the structures across the state, said Acting SHA Administrator Darrell B. Mobley.
Public Schools report little to no damage
In St. Mary's County, school system personnel inspected each building in the inventory to ensure they were structurally safe. They reported last night that all buildings passed the inspection.
Officials in Calvert County say they have done a visual check of every school building. While there is some cracking in plaster and seams, there are no visible signs of structural damage, no reports of broken glass, and no indication of the compromise of any structure, reports Jack Smith, Ph.D., Superintendent of Schools. The one issue they discovered is a crack in the cover of the sidewalk near the entrance of Huntingtown High School. "We have no reason to believe that the sidewalk cover is seriously damaged, but as a precaution we will not use the main entrance of HHS
until we have a structural engineer examine the supporting masonry," wrote
In Charles County, school officials say all schools, centers and offices have been checked for damage and were determined to be safe for use. Buildings were checked by principals, building service managers, and building service staff members. Many buildings have minor issues, such as interior and exterior cracks, loose ceiling tiles, cracked windows or items knocked off walls and shelves. Maintenance staff is working to repair any damage.
Report damaged buildings
The Maryland Historical Trust, the State Historic Preservation Office, is compiling information about damage to older and historic buildings throughout Maryland from the earthquake. If there is a building in your community that has been damaged, visit the following site to share that information: http://mht.maryland.gov/earthquake.html
This information will help the Maryland Historical Trust understand and prioritize reviews for tax credit, easements, and other programs we administer, as well as develop plans for dealing with future natural disasters.
Calvert County businesses owners who believe there has been damage to their buildings as a result of the earthquake are advised to contact the Calvert County Emergency Operations Center (EOC) at 410-535-0314 or 0396.
Calvert County citizens who have concerns about building damage can call the
county Division of Inspections and Permits at 410-535-2155 for referral to
independent structural engineers.
For structural damage reports in St. Mary's County, call 301-475-4911.
Gore Bolton of Bolton & Associates in La Plata, a professional engineer who specializes in inspections, says any damage caused by the moderate temblor might not be obvious.
I would look for any obvious failures, like cracks or settling in the basement walls or foundation of a building, Bolton said. Unlike beauty, structural failure is more than skin deep. In addition, checking for any broken utilities either within or connecting to a building, like water, gas and electric, are also important to identify. Any trouble here is an obvious danger in the short term, but it also indicates a lot of movement that could result in future failures. Its important to have any problem you might suspect in a building of yours be inspected by a qualified engineer.
Was there panic in the streets?
Sheriff Timothy K. Cameron, of St. Mary's Co., reported that emergency
dispatchers received an extremely high number of 911 calls immediately following
the earthquake. "The dispatchers were able to address callers' inquiries and
dispel rumors," wrote Cameron. "Although some buildings received minor
structural damage, I am happy to report no one was injured."
Overall Sheriff Cameron said the public remained calm, allowed additional time
when traveling during the afternoon commute, and was extremely helpful in
notifying county officials of potential hazards.
Government loans available for distressed businesses
If your business or private, nonprofit organization has suffered physical damage or has sustained economic injury after a disaster, you may be eligible for financial assistance from the U.S. Small Business Administration (SBA). If your businessregardless of sizeis located in the declared disaster area, you may apply for a long-term, low-interest loan to repair or replace damaged property.
Even if your property was not damaged and you are a small business owner or a private, nonprofit organization, you may apply for a working capital loan from the SBA to relieve the economic injury caused by the disaster.