M6.4 Al Hoceima, Morocco Earthquake of 24 February 2004 · M6.4 Al Hoceima, Morocco Earthquake of...
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Transcript of M6.4 Al Hoceima, Morocco Earthquake of 24 February 2004 · M6.4 Al Hoceima, Morocco Earthquake of...
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M O R O C C O
S P A I N
Ceuta (Spain)
Gibraltar (U.K.)
S t r a i t o f G i b r a l t a rM E D I T E R R A N E A N S E A
E r R i f
ALGERIA
M o y e n A t
l a s
B e n
i
G u
i l
O u
e d
M o
u l
o u
y a
O u e d S e l o u
Epicentral Area
Melilla (Spain)
EasternCentre-North
Andalucia
North-West
Centre-South
Tlemcen
Ceuta
FES
TAZA
Adra
NADOR
BurgoAlora
Berja
Burgo
Sefrou
MEKNES
JERADA
Rualam
Umeras
Umeras
Martil
TANGER
MALAGA
Motril
OlveraCadiar
Durcal
Missour
Guercif
MELILLA
Uad Lau
TETOUAN
ALMERIA
Ain leuh
Tilmirat
El Hajeb
Mahirija
Berguent
Taourirt
Taounate
El Aioun
Ouezzane
Tarquist
Taguidit
El Jabha
LA LINEA
Estepona
Marbella
Aguelmous
Sellaouit
Guenfouda
Dar Drius
GIBRALTAR
ALGECIRAS
Almunecar
Ahermoumou
Chechaouen
Al Hoceima
Fuengirola
Sidi Kassem
Fes el Bali
Ulad Mohand
Sidi Slimane
Outat el Hajj
Sidi Abdallah
Mechra bel Ksiri
Imouzzer Du Kandar
Cuevas del Becerro
Almis des Marmoucha
Vejer de la Frontera
Alhaurin de la Torre
Arcos de la Frontera
Jimena de la Frontera
Alcala de Los Gazules
Las Cubezas de San Juan
Moulay Idriss du Zerhoun
1624
1926
1755
18211848
1808
1909
1777
15221680
1356
18041825
19561884
1971
2000
1996
1964 1970
1996
1968
196819941994
19931992
1987
20021999
1980
20021975
19971997
1994
1993
2004
Azrou
Ahfir
CEUTA
Ifrane
Tarifa
Matarka
BERKANE
Ubrique
Boulmane
Oued Ouahar
KSAR EL KEBIR
Bour Oulad Isrhi
Map prepared by U.S. Geological SurveyNational Earthquake Information Center27 February 2004Map not approved for release by Director USGS
EARTHQUAKE SUMMARY MAP 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.
Seismic hazard is expressed as peak ground acceleration (PGA) on firm rock,in meters/sec², expected to be exceededin a 50-yr period with a probability of 10 percent.
M6.4 Al Hoceima, Morocco Earthquake of 24 February 2004
0 50 100 150 20025
Kilometers
SCALE 1:1,200,000
Albers Equal-Area Projection
DISCUSSION
This earthquake occurred near the eastern end of the Rif mountainbelt, which is part of the diffuse boundary between the African and Eurasian plates. The epicentral region is the most seismically active area in Morocco. The geologically prominent Nekor fault lies about 30 km to the southeast of the February 24 earthquake. Numerous northeast-southwest trending faults occur in the epicentral region, and the preliminary determination of the earthquake's focal mechan-ism is consistent with the earthquake having occurred as slip on one of these faults. The February 24, 2004, quake occurred near the epi-center of the May 26, 1994, magnitude 6.0 Al Hoceima earthquake that injured one person and caused significant damage to adobe buildings.
The most deadly Moroccan earthquake in the 20th century was the 1960 magnitude 5.7 Agadir earthquake that killed 12,000 people and injured 25,000. Agadir is in western Morocco, about 750 km southwest of the February 24, 2004, earthquake.
AL HOCEIMA, MOROCCO
24 February 2004 02:27:46 UTC
35.235° N., 3.963° W.
Depth 1 km (poorly constrained)
Mw = 6.4 (USGS)
This earthquake occurred near the Moroccan port city of Al Hoceima.
More than 571 persons were reported killed and over 400 injured. Wide-
spread damage to unreinforced mud brick and stone structures and con-
crete apartment buildings was reported in Al Hoceima and surrounding
villages. Early reports said that the worst damage was in the villages of
Ait Kamara, Tamassint, Imzourn, and Tizi Ayash. Officials reported that
more than 20,000 persons were homeless, either because their dwellings
were destroyed or from fear of aftershocks.
The earthquake was experienced both east and west of Al Hoceima
and was felt widely in southernmost Andalucia and Murcia Provinces
of Spain.
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Seismicity of Morocco and Vicinity
M O R O C C O
A L G E R I A
W E S T E R N S A H A R A( M o r o c c o )
S P A I N
Gibraltar (U.K.)
Ceuta (Spain)
A T L A N T I C O C E A N
Str. o f Gibraltar
M E D I T E R R A N E A NS E A
Fuerteventura
Lanzarote
Canary Islands(Spain) A T
L
A S
M
O
U
N
T
A I
N
S
H a u t A t l a s
M o y e
n
A t
l a s
A t l as S
a h a r i en
H a u t s
P l at e
a u x
S A H A R A
EPICENTRALAREA
Tangier
Rabat
Casablanca
Agadir
Melilla (Spain)
S o u t h
B e c h a r
T i n d o u fA d r a r
E a s t e r n
C e n t r e
T e n s i f t
N a a m a
C e n t r e - S o u t hC e n t r e - N o r t h
N o r t h - W e s t
S a g u i a e l H a m r a
A n d a l u c i a
T l e m c e nS i d i b e l A b b e s
O r a nM a s c a r a
E l B a y a d h
S a i d aA i n T e m o u c h e n t
E l B a y a d h
C a n a r i a s
C a n a r i a s
T i r i s Z e m m o u r
M o s t a g a n e m
1960
1731
17571755
18191276 19101660
19091777
13201755
15221680
1356 18041825 195418841722
19851972
19712001
1972 1996 1964 197019961968196819941994
199519872002
1999
19911969 19801969
1969
19751969
19641990
1972 20021993 1978
1973 19971997 19942000
1997196519931986
19691999
2004
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Kilometers
SCALE 1:6,000,000
Albers Equal-Area Projection
14° 13° 12° 11° 10° 9° 8° 7° 6° 5° 4° 3° 2° 1°
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Generalized Seismic Hazard
M O R O C C O
A L G E R I A
W E S T E R N S A H A R A( M o r o c c o )
S P A I N
Gibraltar (U.K.)
Ceuta (Spain)
A T L A N T I C O C E A N
Str. o f Gibraltar
M E D I T E R R A N E A NS E A
Fuerteventura
Lanzarote
Canary Islands(Spain) A T
L
A S
M
O
U
N
T
A I
N
S
H a u t A t l a s
M o y e
n
A t
l a s
A t l as S
a h a r i en
H a u t s
P l at e
a u x
S A H A R A
EPICENTRALAREA
Tangier
Rabat
Casablanca
Agadir
Melilla (Spain)
S o u t h
B e c h a r
T i n d o u fA d r a r
E a s t e r n
C e n t r e
T e n s i f t
N a a m a
C e n t r e - S o u t hC e n t r e - N o r t h
N o r t h - W e s t
S a g u i a e l H a m r a
A n d a l u c i a
T l e m c e nS i d i b e l A b b e s
O r a nM a s c a r a
E l B a y a d h
S a i d aA i n T e m o u c h e n t
E l B a y a d h
C a n a r i a s
C a n a r i a s
T i r i s Z e m m o u r
M o s t a g a n e m
1960
1731
17571755
18191276 19101660
19091777
13201755
15221680
1356 18041825 195418841722
19851972
19712001
1972 1996 1964 197019961968196819941994
199519872002
1999
19911969 19801969
1969
19751969
19641990
1972 20021993 1978
1973 19971997 19942000
1997196519931986
19691999
2004
0 100 200 300 40050
Kilometers
SCALE 1:6,000,000
Albers Equal-Area Projection
EXPLANATIONMainshock
24 February 2004
Modern Earthquakes
Historic Earthquakes
Volcano
Seismic Hazard
0 - 0.2 m/sec²
0.2 -0.4
0.4 - 0.8
0.8 - 1.6
1.6 - 3.2
3.2 - 4.6
Plate Boundary
Continental Convergent
Continental Rift
Continental RL Transform
Oceanic Convergent
Oceanic RL Transform
EXPLANATIONMainshock
24 February 2004
Largest Historic Earthquakes
1276 - 1963
Largest Modern Earthquakes
1964 - 2002
PDE Earthquakes M�4
1973 - 2004
Plate Boundary
Continental Convergent
Continental Rift
Continental RL Transform
Oceanic Convergent
Oceanic RL Transform
Volcano
EXPLANATIONMain Shock
24 February 2004
Aftershocks
2.6 - 2.9
3.0 - 3.4
3.5 - 3.9
4.0 - 4.4
4.5 - 4.9
5.0 - 5.4
Modern Earthquakes
Historic Earthquakes
Generalized Plate Boundary
Continental Convergent
Continental RL Transform
14° 13° 12° 11° 10° 9° 8° 7° 6° 5° 4° 3° 2° 1°
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Tectonic Setting
M O R O C C O
A L G E R I A
W E S T E R N S A H A R A( M o r o c c o )
S P A I N
Gibraltar (U.K.)
Ceuta (Spain)
A T L A N T I C O C E A N
Str. o f Gibraltar
M E D I T E R R A N E A NS E A
Fuerteventura
Lanzarote
Canary Islands(Spain) A T
L
A S
M
O
U
N
T
A I
N
S
H a u t A t l a s
M o y e
n
A t
l a s
A t l as S
a h a r i en
H a u t s
P l at e
a u x
S A H A R A
EPICENTRALAREA
Tangier
Rabat
Casablanca
Agadir
A F R I C A N P L A T E
E U R A S I A N P L A T E3.8 mm/yr
5.0 mm/yrMelilla (Spain)
S o u t h
B e c h a r
T i n d o u fA d r a r
E a s t e r n
C e n t r e
T e n s i f t
N a a m a
C e n t r e - S o u t hC e n t r e - N o r t h
N o r t h - W e s t
S a g u i a e l H a m r a
A n d a l u c i a
T l e m c e nS i d i b e l A b b e s
O r a nM a s c a r a
E l B a y a d h
S a i d aA i n T e m o u c h e n t
E l B a y a d h
C a n a r i a s
C a n a r i a s
T i r i s Z e m m o u r
M o s t a g a n e m
1960
1731
17571755
18191276 19101660
19091777
13201755
1522
18041825 195418841722
19851972
19712001
1972 1996 1964 197019961968196819941994
199519872002
1999
19911969 19801969
1969
19751969
19641990
19721993 1978
1973 19971997 1994
196519931986
19691999
2004
0 100 200 300 40050
Kilometers
SCALE 1:6,000,000
Albers Equal-Area Projection
RELATIVE PLATE MOTIONS
The relative motion of adjacent tectonic plates is depicted on the map by short vectors shown at selected locations on the plate boundary. In this presentation, one of the plates is defined as the reference plate. The vector therefore repre-sents the direction of motion of the adjacent plate relative to the reference plate. The rate of relative motion is labeled next to the vector.
The components of the vector perpendicular and parallel to the plate margin approximate converg-ent/divergent and transverse direction of motion between the plates, respectively. As viewed from the reference plate, an inward directed component suggests convergence at and near the plate bound-ary that may be expressed as crustal folding, up-lift, thrust faulting, or plate subduction. Similarly, an outward directed component suggests plate divergence such as would be expected at a zone of crustal spreading. Transcurrent or transform faulting would be expected when the dominant vector component is parallel to the plate margin.
In this case, the African plate is moving relative tothe Eurasian reference plate at velocities 5 mm/yror slower. The relatively slow convergence of thetwo plates results in a diffuse zone of seismicity that extends across northern Morocco into the Atlantic Ocean west of the Strait of Gibraltar.
DATA SOURCES
EARTHQUAKES AND SEISMIC HAZARD USGS, National Earthquake Information Center European-Mediterranean Seismological Center (EMSC) IASPEI, Centennial Catalog (1900 - 1999) and extensions (Engdahl and Villaseñor, 2002) HDF (unpublished earthquake catalog) (Engdahl, 2003) Global Seismic Hazard Assessment Program UN Office for the Coordination of Humanitarian Affairs
PLATE TECTONICS PB2003 (Bird, 2003)
VOLCANOES Smithsonian Institution, Global Volcano Program
BASE MAP NIMA and ESRI, Digital Chart of the World USGS, EROS Data Center
NEWS SOURCES Africa Daily http://www.africadaily.com Associated Press (AP) Channel News Asia http://www.channelnewsasia.com/stories CNN http://www.cnn.com/2004/WORLD Reuters http://www.reuters.com USAToday http://www.usatoday.com/new/world
REFERENCES
Bird, P., 2003, An updated digital model of plate boundaries: Geochem. Geophys. Geosyst., v. 4, no. 3, pp. 1027- 80.
Engdahl, E.R. and Villaseñor, A., 2002, Global Seismicity: 1900 - 1999, chap. 41 of Lee, W.H.K., and others,eds., International Earthquake and Engineering Seismology, Part A: New York, N.Y., Elsevier Academeic Press, 932 p.
Engdahl, E.R., Van der Hilst, R.D., and Buland, R.P., 1998, Global teleseismic earthquake relocation with improved trav- el times and procedures for depth determination: Bull. Seism. Soc. Amer., v. 88, p. 722-743.
NOTE ON SEISMICITY
The seismicity portrayed in these maps is drawn from three separate earthquake cat-alogs that are characterized by varying lev-els of accuracy and reliability. The largest and best-located earthquakes of the modern seismological era (1964 - 2002) are drawn from an unpublished catalog of Engdahl (2003). The largest and least well-located historic earthquakes (1276 - 1963) are drawn from a catalog of significant global earthquakes from NOAA. A representative sample of smaller (magnitude � 4.0) and relatively well-located earthquakes (USGS PDE) from 1973 - 2004 is included on this map to illustrate the diffuse nature of the African - Eurasian plate boundary.
Photos: Agence France Presse
