m4.6 fort payne, alabama earthquake of 29 april 2003 · 29-04-2003 · 86°30´ 86°00´g 85°30´...
TRANSCRIPT
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86°30´ 86°00´ 85°30´ 85°00´ 84°30´
86°30´ 86°00´ 85°30´ 85°00´ 84°30´
33°30´
34°00´
34°30´
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TENNESSEE
ALABAMA GEORGIA
TENNESSEE
ALA
BA
MA
GE
OR
GIA
Gun
ters
ville
Lak
e
Tenn
esse
e Ri
ver
Weiss Lake
Allatoona Lake
Chickamauga Lake
Coos
a Rive
r
Coos
a Ri
ver
Epicentral Area
JACKSON
DE KALB
FLOYD
ST CLAIR
CALHOUN
ETOWAH
MARION
POLK
CHEROKEE
FRANKLIN
BARTOW
HAMILTON
WALKER
MARSHALL
CLEBURNE
COBB
POLK
CARROLL
GORDON
MURRAY
GRUNDY
BRADLEY
MADISON
MCMINN
DADE
COFFEE
BLOUNT
PAULDING
FULTON
HARALSON
CHATTOOGA
WHITFIELD
GILMER
DOUGLAS
CHEROKEE
SEQUATCHIE
LINCOLN
CATOOSA
MOORE
TALLADEGA
MEIGSBEDFORD
RHEA
PICKENS
BLEDSOE
FANNIN
FAYETTE
CULLMAN
SHELBY
ROME
Soddy
Heflin
Bremen
Centre
Dalton
Etowah
Athens
Dayton
Oneonta
GADSDEN
Calhoun
Decherd
Fairburn
ANNISTON
PiedmontMARIETTA
Rockmart
Whitwell
Pell City
Cedartown
TULLAHOMA
Carrollton
Tallapoosa
Fort Payne
Rainsville
SCOTTSBORO
La Fayette
Chatsworth
Bridgeport
Winchester
Tracy City
Manchester
Springville
ALBERTVILLE
Adairsville
CHATTANOOGA
SHELBYVILLE
Cartersville
South Pittsburg
2003
1984
19842001
2001
19861994
19971993
1985
1995
GENERAL INTEREST PRODUCT XXXU.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY
DISCLAIMER
Base map data, such as place names and politicalboundaries, are the best available but may not be current or may contain inaccuracies and thereforeshould not be regarded as having official significance.
M4.6 Fort Payne, Alabama Earthquake of 29 April 2003
92° 91° 90° 89° 88° 87° 86° 85° 84° 83° 82° 81° 80° 79°
78°
92° 91° 90° 89° 88° 87° 86° 85° 84° 83° 82° 81° 80° 79°
78°
29°
30°
31°
32°
33°
34°
35°
36°
37°
29°
30°
31°
32°
33°
34°
35°
36°
37°
Earthquake History of the Southeastern U.S.
G E O R G I A
F L O R I D A
M I S S I S S I P P I A L A B A M A
T E N N E S S E E N O R T H C A R O L I N A
S O U T HC A R O L I N A
K E N T U C K Y V I R G I N I AM I S S O U R I
A R K A N S A S
L O U I S I A N A
A T L A N T I CO C E A N
G u l f o f M e x i c o
M i
s s
i s s
i p
p i
R i
v e
r
C u m
b e
r l a
n d
P
l a t
e a
u
A P P
A L A
C H
I A N
M T
S.
P i e
d m o
n t
T e n n e s e e R.
Nashville
Charleston
New Orleans
Memphis
BirminghamAtlanta
Charlotte
Jacksonville
MAIN MAP
C o a s t a l P l
a i n
1972
1970
19631962
1959
1957
1956
1956
1955
1954
1945
1938
1934
1931
1930
1927
1924
1923
1918
1916 1914
1911
1909
19031903
1903
1899
1898
1895
1886
1883
1878
1878
1875
1861
1852
1850
1843
1843
1817
1811
2002
19991997
1997
1991
1991
1990
1986
1981
1976
19751975
1974
1974
1974
2003
92° 91° 90° 89° 88° 87° 86° 85° 84° 83° 82° 81° 80° 79°
78°
92° 91° 90° 89° 88° 87° 86° 85° 84° 83° 82° 81° 80° 79°
78°
29°
30°
31°
32°
33°
34°
35°
36°
37°
29°
30°
31°
32°
33°
34°
35°
36°
37°
Seismic Hazard of the Southeastern U.S.
G E O R G I A
F L O R I D A
M I S S I S S I P P I A L A B A M A
T E N N E S S E E N O R T H C A R O L I N A
S O U T HC A R O L I N A
K E N T U C K Y V I R G I N I AM I S S O U R I
A R K A N S A S
L O U I S I A N A
A T L A N T I CO C E A N
G u l f o f M e x i c o
Nashville
Charleston
New Orleans
Memphis
BirminghamAtlanta
Charlotte
Jacksonville
MAIN MAP
New MadridSeismic Zone
Eastern TennesseeSeismic Zone
South CarolinaSeismic Zone
2003
2002
19991997
1997
1996
1992
1991
19911990
1989
19871987
1986
1984
1981
1976
19751975
1975
1974
1974
1973
1972
1967
1963
1957
1957
1956
1956
1956
1954
1945
1934
1931 1931
1930
19281918
1916
1916
1914
1913
1913
1911
1903
1903
1899
1898
1886
1883
1878
1875
1861
1858 1852
1850
1817
0 100 200 300 40050
Kilometers
SCALE 1:5,000,000Albers Equal-Area Projection
0 100 200 300 40050
Kilometers
SCALE 1:5,000,000Albers Equal-Area Projection
0 10 20 30 405
Kilometers
SCALE 1:1,000,000Albers Equal-Area Projection
DISCUSSION
TECTONIC SETTING AND SEISMICITY CONTEXT
The Eastern Tennessee seismic zone, which extends from southwest Virginia to northeast Alabama, is one of the most active earthquake areas in the Southeast. Although the zone has not had a large earthquake in historic times, a few earthquakes have caused slight damage. The largest recorded earthquake in this seismic zone was a magnitude 4.6 that occurred in 1973 near Knoxville. Sensitive seismo-graphs have recorded hundreds of earthquakes too small to be felt in this seismic zone. Small, non-damaging, felt earthquakes occur about once a year.
Earthquakes in the central and eastern U.S., although less frequent, are typically felt over a much broader region than the western U.S. East of the Rockies, an earthquake can be felt in an area as much as ten times greater than a similar magnitude earthquake in the western U.S. For example, a magnitude 4.0 eastern U.S. earthquake typically can be felt at many locations as far as 100 km (60 mi) from where it occurred, and it might or might not cause damage near its source. A magnitude 5.5 eastern US earthquake usually can be felt as far as 500 km (300 mi) in most directions and can cause damage out to 40 km (25 mi).
FAULTS
At plate boundaries, earthquakes can commonly be related to specific faults or fault systems. In contrast, in the eastern Tennessee seismic zone the relation between faults and earthquakes is more enigmatic. The Eastern U.S. is far from the plate boundaries, the nearest of which are in the center of the Atlantic Ocean and in the Caribbean Sea. No active faults are known to reach the surface in the region, although the area is laced with ancient faults that developed as the Appalachian Mountains formed several hundred million years ago. The larger faults, particularly those that have been exposed at the Earth's surface by erosion, are likely to have been mapped by geologists. Unknown but probably numerous smaller or more deeply buried faults remain undetected. Even those faults that are mapped at the surface are poorly located at earthquake depths. Accordingly, few, if any, earthquakes in the eastern Tennessee seismic zone can be linked to known faults, and it is difficult to determine if a specific fault could still slip and cause an earthquake. As in most other areas east of the Rockies, the best guide to earthquake hazards in the seismic zone is the earthquakes themselves.
DISCUSSION (continued)
PAST EARTHQUAKES IN ALABAMA
The documented history of small earthquakes in Alabama spans about 100 years and includes about a half dozen small- to moderate-sized damaging events. The largest recent earthquake recorded in the State was a magnitude 4.9, which occurred south of the Eastern Tennessee seismic zone near Atmore, Alabama, on October 24, 1997. For an in-depth summary of historical earthquake activity in the State, see theEarthquake History of Alabama (see Online Resources at bottom of map).
SEISMIC MONITORING IN ALABAMA
The U.S. Geological Survey works in cooperation with the Center for Earthquake Research and Information (CERI) at the University of Mem-phis to monitor seismicity in the Alabama region. In response to the 1997 magnitude 4.9 Atmore, Alabama earthquake, the U.S. Geological Surveyin cooperation with the State Survey of Alabama installed a seismic monitoring station near Birmingham, Alabama in 2001. This station is a key part of an upgraded seismic monitoring network being implemented by the USGS as part of its Advanced National Seismic System (ANSS). Additional stations are planned for the southeastern U.S., pending the allocation of Federal funds.
IMPACT OF THE 29 APRIL 2003 EARTHQUAKE
This earthquake produced very limited damage. Cracked foundations and bricks fallen from chimneys were reported at Fort Payne. The water system at Valley Head also reported muddy water. Some schools in the region were closed as a precaution.
PUBLIC RESPONSE TO THE 29 APRIL 2003 EARTHQUAKE
Thousands of web surfers recorded their observations of thisearthquake on a USGS internet site designed to compile public observations into an integrated shaking map for the epicentral region. This "Did You Feel It" web site not only provides a concise summary of the distribution of perceived shaking, but it also provides researchers with data they need to supplement limited seismic recordings. The public is encouraged to visit the "Did You Feel It" site and record their own observations.
ALABAMA
29 April 2003 08:59:38.59 UTC34.508°N., 85.612°W.Depth 15 kmMagnitude = 4.6
This earthquake was felt widely over the southeastern United States.Slight damage (intensity VI) at Fort Payne, Graylesville and Valley Head. Felt (intensity V) at Flat Rock, Henagar, Higdon, Leesburg, Mentone, Rainsville and Sylvania. Felt in parts of Alabama, Georgia, Kentucky, Mississippi, North Carolina, South Carolina and Tennessee.
EXPLANATIONMain Shock 29 April 2003
2003
Aftershocks 29 April 2003
Recent Earthquakes
1986
Magnitude Classes
M1.0 - 1.9
2.0 - 2.9
3.0 - 3.9
4.0 - 4.9
Urbanized Areas
EXPLANATIONMain Shock 29 April 2003
2003
Recent Earthquakes 1973 - 2003
1975
Historic Earthquakes Pre-1973
1914
Magnitude Classes
M3.0 - 3.9
4.0 - 4.9
5.0 - 5.9
6.0 - 6.9
7.0 - 7.9
8.0 - 8.9
Urbanized Areas
92° 91° 90° 89° 88° 87° 86° 85° 84° 83° 82° 81° 80° 79°
78°
92° 91° 90° 89° 88° 87° 86° 85° 84° 83° 82° 81° 80° 79°
78°
29°
30°
31°
32°
33°
34°
35°
36°
37°
29°
30°
31°
32°
33°
34°
35°
36°
37°
ANSS Backbone Stations in the Southeastern U.S.
G E O R G I A
F L O R I D A
M I S S I S S I P P I A L A B A M A
T E N N E S S E E N O R T H C A R O L I N A
S O U T HC A R O L I N A
K E N T U C K Y V I R G I N I AM I S S O U R I
A R K A N S A S
L O U I S I A N A
A T L A N T I CO C E A N
G u l f o f M e x i c o
Nashville
Charleston
New Orleans
Memphis
BirminghamAtlanta
Charlotte
Jacksonville
MAIN MAP
2003OXF
WVT
ATAL
ENGA
VBMS
LRAL NHSCGOGA
PLALCBSC
MONCSWET
SEKY
DATA SOURCES
EARTHQUAKES AND SEISMIC HAZARD USGS, National Earthquake Information Center CERI, University of Memphis SLUEC, Saint Louis University IASPEI, Centennial Catalog (1900 - 1999) Handbook of Seismology and Earthquake Engineering Global Seismic Hazard Assessment Program
BASE MAP NIMA and ESRI, Digital Chart of the World USGS, EROS Data Center
SCALE 1:5,000,000Albers Equal-Area Projection
0 100 200 300 40050
Kilometers
Internet Intensities
EXPLANATIONANSS Seismic Stations
Cooperating
Planned
USNSN
Map prepared by U.S. Geological SurveyNational Earthquake Information Center23 June 2003Map not approved for release by Director USGS
Representative Digital
Seismograms
Lakeview Retreat, AL (LRAL)
Pickwick Lake, AL (PLAL)
0 20 sec
P
P
S
S
COMMUNITY INTERNET INTENSITY MAP
The Community Internet Intensity Map (CIIM) summarizes the online questionnaire responses provided by Internet users. An intensity number is assigned to each community from which a filled-out CIIM questionnaire was received; each intensity value reflects the effects of earthquake shaking on the people and structures in the community.The color-coded ZIP Code zone on the map represents the average of the individual intensity values in thatZIP Code zone.
This map is found at: http://pasadena.wr.usgs.gov/shake/cus/STORE/Xteak/ ciim_display.html
ADVANCED NATIONAL SEISMIC SYSTEM
The Advanced National Seismic System (ANSS) will be a nation-wide network of at least 7000 shaking measurement systems, both on the ground and in buildings that will make it possible to provide emergency response personnel with real-time earthquake informa-tion, provide engineers with information about building and site re-sponse, and provide scientists with high-quality data to understand earthquake processes and solid earth structure and dynamics.
ONLINE RESOURCES
USGS Earthquake Program http://earthquake.usgs.govCommunity Internet Intensity Map (CIIM) http://pasadena.wr.usgs.gov/shake/cus/html/background.htmlAdvanced National Seismic System (ANSS) http://www.anss.orgCenter for Earthquake Research and Information http://www.ceri.memphis.eduSaint Louis University Earthquake Center http://www.eas.slu.edu/Earthquake_CenterEarthquake History of Alabama http://neic.usgs.gov/neis/states/alabama/alabama_history.htmlGeological Survey of Alabama http://www.gsa.state.al.us/
Seismic hazard is expressed as peak ground acceleration (PGA) on firm rock, in percent g, expect-ed to be exceeded with a proba-bility of two percent in a 50- year period
EXPLANATION
Seismic Hazard
170 - 180 %g Highest Hazard
160 - 170
150 - 160
140 - 150
130 - 140
120 - 130
110 - 120
100 - 110
90 - 100
80 - 90
70 - 80
60 - 70
50 - 60
40 - 50
30 - 40
20 - 30
10 - 20
2 - 10 %g Lowest Hazard
Prepared in cooperation with theUniversity of Memphis Center for Earthquake Research and Information
and the Saint Louis University Earthquake Center