EDUCATE

E = Educate the public about hazards and response       planning

Earthquakes

Earthquake is a term used to describe both sudden slip on a fault, and the resulting ground shaking and radiated seismic energy caused by the slip, or by volcanic or magmatic activity, or other sudden stress changes in the earth.

Though an earthquake in the Mobile area would be extremely rare, it is best to know Alabama’s earthquake history and what to do in the event of a quake.

Alabama’s Earthquake History

The known seismic history of Alabama spans about 100 years for local earthquakes. For shocks outside the State borders that caused damaged to cities in Alabama, the history can be traced to 1811 - 1812, when three great (estimated magnitude 8 or greater on the Richter scale) earthquakes centered in Missouri may have reached intensity VII in the northern and/or central sections. These gigantic earthquakes were comparable to the San Francisco shock in 1906 and were felt over 2 million square miles, more than half of the total area of the United States.

Historical records indicate the first earthquake of consequence in Alabama shook residents of Sumter and Marengo Counties, located in the western part of the State, on February 4, 1886. A similar shock occurred nine days later, on February 13. Both were reported felt at communities along the Tombigee River, but caused no damage. Only six months later, the destructive Charleston, South Carolina, shock that was felt in cities all over the Eastern United States occurred. This shock, located about 400 miles east of Alabama's border, caused minor damage in the northeastern part of the State.

In 1916 on October 18, a strong earthquake occurred on an unnamed fault east of Birmingham. It was apparently most strong at Easonville. Near the epicenter, chimneys were knocked down, windows broken, and frame buildings "badly shaken." It was noted by residents in seven States and covered 100,000 square miles.

Another tremor that damaged the Birmingham area occurred on April 23, 1957. Centered near the Tennessee River below Guntersville Dam, the earthquake shook residents in southern Tennessee, western Georgia, and most of northern and central Alabama. Earthquake records for that year state: "Felt by, awakened, and alarmed many. Minor damage to several chimneys; one report of cement steps cracked in two; and several small cracks in walls. Table-top items tumbled to the floor."

A shock centered in the Huntsville area on August 12, 1959. Though felt over a small area of southern Tennessee and northern Alabama, it shook bricks from chimneys at Hazel Green; damaged one chimney and a newly constructed concrete block building at Meridianville; shook violently the buildings at New Sharon, knocking canned goods from shelves and sending frightened residents fleeing from their homes; and cracked plaster and knocked groceries from shelves at Huntsville.

Additional earthquakes (intensity V category) listed for this State that were minor and caused no damage centered near Rosemary, western Alabama, in June 1917; in the Scottsboro area northeast of Huntsville in June 1927; at Cullman, northern Alabama, in May 1931; and in the Anniston area in May 1939.

A strong earthquake in southern Illinois in November 1968 caused intensity V effects in several localities in northern Alabama. The shock was the strongest in Illinois since 1895, and was felt over a half-million square miles in 23 States.

[The above history was abridged from Earthquake Information Bulletin, Volume 2, Number 1, January-February 1970.]

1975 Aug 29 04:22 4.4M Intensity VI
Palmerdale, Alabama ( 33.659N 86.5880W )
The earthquake cracked a sheetrock ceiling and shifted lamps on tables at Palmerdale, north of Birmingham. It caused slight damage at Watson, where furniture was displaced slightly. Also felt in southern Tennessee.

1989 Aug 20 00:03 3.9M Intensity VI
Near Littleville, Alabama ( 34.736N 87.6450W )
A Colbert County official reported that, south of Florence between Littleville and Russellville, a basement wall collapsed beneath a house. Only slight damage was reported north of the epicenter at Florence, where windows were cracked and hairline cracks formed in plaster. Also felt in Lauderdale, Lawrence, and Morgan Counties in northwest Alabama and Lawrence County in south-central Tennessee.

1997 Oct 24 08:35 4.9M Intensity VI
Near Brewton, Alabama ( 31.118N 87.3390W )
Felt (VI) at Brewton, Canoe and Lambeth; (V) at Atmore, Flomaton, Frisco City and Huxford; (IV) at Perdido and Robinsonville; (III) at Butler, Demopolis, Goodway, Mobile and Uriah. Felt (V) at Century; (IV) at McDavid, Pensacola and Walnut Hill; (III) at Milton, Florida. Felt (IV) at Leakesville, Mississippi. Also felt at Megargel; Elgin AFB, Florida; Biloxi and Gulfport, Mississippi.
1999 Jan 18 07:00 4.0M

Alabama ( 33.405N 87.2550W )
Mine collapse.

When an earthquake occurs

How to protect yourself - First, stay calm!

WHEN YOU ARE INDOORS

In your house:

• If you feel shaking, hide underneath a table or desk. If this is not possible, cover your head with a pillow or cushion.
• Do not go outside until the shaking has stopped.
• Open doors and windows to ensure you have escape routes.
• If using gas stoves or other equipment, extinguish all flames immediately (turn off the gas mains)
• Turn off the electricity
• If fire breaks out, use an extinguisher to put out all fires immediately.
• If fire breaks out when using kerosene or cooking oil, do not use water, use something such as a damp shirt to cover the pot and extinguish the flames.
  

In a supermarket or department store:

• If you feel shaking, protect your head with your bag and step away from the shelves.
• Stay close to walls or large pillars.
• Do not rush for exits and follow the directions of staff. When evacuating use the stairs and not the elevators.
• If you are in the elevator and it stops moving, use the emergency phone inside and wait for assistance.

When underground:

• Stay close to walls or large pillars.
• If the lights fail, stay calm and wait for the emergency lighting to come on.
• If fire breaks out and the area fills with smoke, cover your nose and mouth with a handkerchief or towel and escape in the direction from which the cool air is coming and follow the wall to the nearest exit.

WHEN YOU ARE OUTDOORS

In a residential area:

• Quickly move away from stone or block walls and move to a safe place.
• Glass and roof tiles may fall, so move quickly to open areas such as parks and avoid going near buildings.

In a shopping or building arcade:

• Without stopping, protect your head with bags or similar items and evacuate to a park or other open spaces.
• Do not go near buildings, block walls or vending machines.
• Do not go near fallen power lines.
• Be careful of broken glass, signs and other fallen objects.

In a train or subway carriage:

• Hold tightly to straps and rails in case the train or subway stops suddenly.
• If the train or subway stops, do not jump out of windows or attempt to unlock the emergency door and leave the carriage.
• Follow the announcements of train staff and act in a calm manner.

When driving:

• Pull over to the left side of the road or an open space and turn off the engine.
• If police are controlling traffic, follow their directions.
• If leaving your vehicle, leave the key in the lock and the doors unlocked.

OBTAINING ACCURATE INFORMATION

• Pay attention to information given on radio and television and do not react hastily to inaccurate information.
• Refrain from making unnecessary telephone calls. Inquiries made to the Fire Department regarding the situation of the disaster hamper the efforts of emergency services.

PROTECTING MOBILE

In the unlikely event an earthquake occurs in our town, it is possible to consider that communication by telephone will be rendered impossible, roads will be damaged, and the spread of fire will split the functions of the town, decreasing the effectiveness of the fire department and other disaster relief activities. Therefore, we should all cooperate in helping to extinguish fires and assisting those who are trapped under rubble and in damaged buildings.