DOI: 10.1016/j.tecto.2020.228547
论文题名: Seismicity and seismotectonics of Madagascar revealed by the 2011–2013 deployment of the island-wide MACOMO broadband seismic array
作者: Rakotondraibe T. ; Nyblade A.A. ; Wysession M.E. ; Durrheim R.J. ; Rambolamanana G. ; Aleqabi G.I. ; Shore P.J. ; Pratt M.J. ; Andriampenomanana F. ; Rümpker G. ; Rindraharisaona E.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 790 语种: 英语
英文关键词: Faulting
; Broad-band seismic stations
; Diffuse plate boundaries
; Extensional stress
; Extensional tectonics
; Frequency-magnitude distribution
; Normal faulting
; Plate boundaries
; Tectonic features
; Earthquakes
; broadband data
; earthquake magnitude
; focal mechanism
; geophysical array
; seismic method
; seismicity
; seismotectonics
; Madagascar
英文摘要: The seismicity and seismotectonics of Madagascar have been studied using an island-wide distribution of broadband seismic stations. The 28-station MAdagascar-COmoros-MOzambique (MACOMO) array was deployed for a 23-month period between 2011 and 2013. MACOMO data were supplemented by seven temporary stations from the Seismological Signatures in the Lithosphere/Asthenosphere system of Southern Madagascar (SELASOMA) project, ten temporary stations from the Réunion Hotspot and Upper Mantle - Réunions Unterer Mantel project (RHUM-RUM), and 11 permanent stations. A total of 695 earthquakes with magnitudes between ML1 and ML5.3 located within Madagascar were recorded, a new local magnitude scale was developed, and focal mechanisms were determined for 23 well-recorded events. Most of the seismicity is clustered within central Madagascar, forming NW-SE trends in the Ankaratra region and NE-SW trends in the Alaotra and Ankay regions that roughly align with extensional tectonic features. The northern and southern parts of Madagascar also show seismicity clusters that align parallel to existing tectonic features, primarily Precambrian shear zones. Focal mechanisms exhibit a wide orientation of nodal planes, show predominantly normal faulting throughout Madagascar, and provide no evidence for a sharp east-west striking plate boundary between the Lwandle and Somalian plates in the middle of the island. However, a diffuse plate boundary cannot be excluded. We suggest that topographically-generated extensional stresses is the cause of most seismicity, given that significantly fewer earthquakes are located in the lower elevation areas of the island compared to regions of higher elevations. The frequency-magnitude distribution has a b-value of ~1.2 and indicates that events with magnitude ML5 or greater should occur with an average repeat time of ~1.4 years. However, no earthquake exceeding ML6 has been recorded in the last century, suggesting that the frequency-magnitude distribution could be truncated. © 2020 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170689
Appears in Collections: 气候变化与战略
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作者单位: School of Geosciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg, 2050, South Africa; Department of Geosciences, Penn State University, University Park, PA 16802, United States; Department of Earth and Planetary Sciences, Washington University in St. Louis, Campus Box 1169, 1 Brookings Drive, Saint Louis, MO 63130-4899, United States; Institut et Observatoire de Géophysique d'Antananarivo, Université d'Antananarivo, Ambohidempona - B. P 3843, Antananarivo, 101, Madagascar; Institute of Geosciences, Goethe-University Frankfurt, Altenhöferallee 1, Frankfurt, 60438, Germany; GeoForschungs Zentrum (GFZ), Telegrafenberg, Potsdam, 14473, Germany
Recommended Citation:
Rakotondraibe T.,Nyblade A.A.,Wysession M.E.,et al. Seismicity and seismotectonics of Madagascar revealed by the 2011–2013 deployment of the island-wide MACOMO broadband seismic array[J]. Tectonophysics,2020-01-01,790