I\ IDRC -118e " PIERRE GOUIN ARCHIV .1 37072 IDRC-118e EARTHQUAKE HISTORY of ETHIOPIA and the HORN OF AFRICA Pierre Gouin Director of the Geophysical Observatory University of Addis Ababa, Addis Ababa, Ethiopia From 1957 to 1978 This monograph is a companion volume to "Seismic Zoning in Ethiopia" published by the Geophysical Observa- tory, University of Addis Ababa. It gives the primary and secondary sources as well as the interpretation on which the statistical analyses of regional seismic and volcanic hazards were based. Throughout the text, mention ofpolitical boun- daries is intended only to orient the reader and has been resorted to only when other well-known reference points were unavailable. They in no way should be considered as reflecting exact international boundaries. In addition to this publication, IDRC sponsored part of the research between 1974 and 1978 in cooperation with the Geophysical Observatory of the University of Addis Ababa. The views expressed are those of the author and do not necessarily represent the views of the International Development Research Centre. SrC , 31/- /./;- The International Development Research Centre is a public corporation created by the Parliament of Canada in 1970 to support research designed to adapt science and technology to the needs of developing countries. The Centre's activity is concentrated in five sectors: agriculture, food and nutrition sciences; health sciences; information sciences; social sciences; and communications. IDRC is financed solely by the Government of Canada; its policies, however, are set by an international Board of Governors. The Centre's headquarters are in Ottawa, Canada. Regional offices are located in Africa, Asia, Latin America, and the Middle East. ©1979 International Development Research Centre Postal Address: Box 8500, Ottawa, Canada K 1G 3H9 Head Office: 60 Queen Street, Ottawa Gouin, P. IDRC-118e Earthquake history of Ethiopia and the Horn of Africa. Ottawa, Ont., IDRC, 1979, 259 p. : ill. / IDRC publication/ , /seisms/ , /chronology/ , /Ethiopia/, /East Africa/ /seismology/ , / volcanic eruptions/ , /spatial analysis/ , / damage/ , / maps/. UCD: 550.34(63) ISBN: 0-88936-194-0 Microfiche edition available Contents Acknowledgments 5 Introduction 7 Aim and Scope of Monograph 10 Outline of Geological History 11 The Area Surveyed 14 The Data File 16 Structure of the Data File 17 Reference Map of Ethiopia 17 Sources of Information and Selection of Data 17 Dating of Local Historical Events 18 Identification of Localities 20 Earthquake Amplitude Parameters 22 Figures and Graphs 24 Earthquake History of the . Ethiopian Western Plateau (Region A) 25 Southeastern Plateau (Region B) 81 Ethiopian Main Rift, Afar, and the Southern Red Sea (Region C) 91 Aden Western Sector (Region D) 147 Gemu-Gofa and Turkana (Lake Rudolf) Rifts (Region E) 177 Chronological Listing of Seismic and Volcanic Events 189 Discussions and Conclusions 239 Completeness of the Information 242 Spatial Distribution of the Seismic Activity in Ethiopia and the Horn of Africa 245 Eventual Reevaluation of the Seismicity of Ethiopia 247 Bibliography 249 3 : 14-12, 29 A-1(1A -v oil/4°P I s--a7 r414 -474 :1+w-x1(2010i/ n:70;1/1/ till6,44,;Nr1245(b :AL V :a3c0 : (e.7 i?J41 ( 4-041/ :as'407/..a.o7iver:(1404,212;ai 1.41A :ajJab- 199 4 tl q ;4IL4 ; é1? ,c 40 :-Cv_t-1/.64(PLI/G4-d '4h1411491/ :6'141/0 eriezou c1q :1,1.7%46o1l : e.P.geD :4114 : anA &A 044 :agle00 ;IP744-d :-W.1-.F4thain4 ; *d,t7clao 14.3.106Plib :.4d73011 :17tWito:q,U :°7 :*611) ...vp442.49 aNI/4) -:_oriq 7-4 tal4of 0,1/( atrOiq 'arl7C-4/1N:e614,1) :IP.79672.014,14:423,0:Imi 4-#41 : :_t707)(Z1) 0e) SI/1a' (LS7 cf : U- W11/U : elp 1,1371 ::411/#14711(4 :64 Rke :4117 L47- 4i :24->42.0-90.493iN q}.1)1bU :i49'46.4914:11L41/0 ;L(414-4-7,41 :617"fiq itc674,14 : Icb-ehz-,fry :±9(0 :?* b.24/1)-(4 :i910/714.14I :JIPYall .t cg?6P./-y Acknowledgments My gratitude goes first to the staff of the Geophysical Observatory, Univer- sity of Addis Ababa. It was my pleasure to work with them from the opening of the observatory in 1957 until 1978. Without their continuous and friendly cooper- ation, this survey could not have been conducted. For this particular research, I owe sincere thanks to Ato Yirga Tesfaye, the late Emile Cambron, Laika Mariam Asfaw, Paul A. Mohr, Frances M. Dakin, Ato Theodros Tsigé, and Wozerit Bekelech Degefe. In the process of securing original and often unpublished documents, pre- cious aid was supplied by the following: Sergew G. Sellassie, Director of the Ethiopian Church Microfilm Library; Richard Pankhurst, former Director of the Institute of Ethiopian Studies at the University of Addis Ababa; J-P. Rothé, former Director of the Institut de Physique du Globe, Strasbourg; Prof G. Marinelli, University of Pisa, Italy; R. J. Brazee of the Seismology Division, NOAA; J. C. Ruegg and J. C. Lépine, Institut de Physique du Globe, Paris and Arta; W. Rigden, Durham University, England; A. A. Hughes, Deputy Director of the International Seismological Centre, Edinburgh, Scotland; M. Pearlman and P. Clark, Smithsonian Astrophysical Observatory, Cambridge, USA; the Director of the Station Météorologique in Djibouti; and the Editor of the Revell de Djibouti for the authorization to consult their files. Computation facilities were kindly provided by: the Highway Authority in Addis Ababa; R. Lilwall at the Institute of Geological Sciences in Edinburgh; Lynn Sykes at Lamont-Doherty Geological Observatory of Columbia University; W. G. Milne and G. A. McMechan at the Pacific Geoscience Centre in Victoria, Canada; R. W. Girdler at Newcastle upon Tyne University; J. D. Fairhead of Leeds University; and Honeywell Informatique, Montreal, Canada. 5 Special thanks go to Anne Stevens of the Division of Seismology and Geothermal Studies, Department of Energy, Mines, and Resources, Ottawa, for evaluating the first draft of this earthquake history and recommending its publi- cation, and to Anis Samaan-Hanna for his assistance in the translation of foreign texts. Gérard Despatie, M. S. Dubos, and Jérome Gagnier kindly read parts of the manuscript. Authorization to use copyright material is mentioned in appropriate entries. Finally, acknowledgments are also due for a 2-week stay at the Institute of Geological Sciences in Edinburgh authorized by P. L. Willmore; a 3-month stay at Victoria Observatory authorized by K. Whitham and W. G. Milne of the Earth Physics Branch, Department of Energy, Mines, and Resources, Canada; and a 1- year fellowship at Brebeuf College Observatory in Montreal graciously offered by its Director, Father Maurice Buist, S.J. I apologize to those whose names I may have inadvertently omitted; their aid is also gratefully acknowledged. This research was sponsored by the Faculty of Science, University of Addis Ababa, and by a grant from the International Development Research Centre, Canada. Pierre Gouin 6 Introduction Historical records of the last six centuries and more recent instrumental observations reveal that Ethiopia and the northern sector of the Horn of Africa have been almost continuously jolted by earth tremors and, less frequently, by outbursts of volcanic activity. A highly dissected surface geology, expressed by complicated networks of spectacular faults with vertical throws, often scaled in thousands of metres, and altimetric profiles ranging from below sea level to 3500 metres above it, bear witness that telluric activity is not a phenomenon of recent historical as opposed to geological origin (Fig. 1). If we restrict the telluric activity in this region of northeastern Africa to the rifting process only, it dates back to the fissuring of the Nubian swell, which created the three-branch rift system comprised of the Ethiopian, the Red Sea, and the Gulf of Aden rifts. Rifting in northeastern Africa started some 30 million years ago when the earth's crust, uplifted by a lithothermal system of forces (Gass 1970a,b) generated by a stationary hot spot in the underlying mantle (Burek 1975; Burke and Whiteman 1973; Burke and Wilson 1976), reached the breaking point and fissured along the axes of maximum uplift. During these 30 million years, three major epirogenic episodes can be identified (Gass 1970a,b; Mohr 1971a,b,c). However, the background seismic and volcanic noise caused by crustal readjustments to the vertical forces of alternate doming and subsiding, and to horizontal tensions and shears progressively accumulating along the boundaries of newly formed tectonic plates, must have been practically continuous during these millions of years and will continue for many centuries to come. Earthquakes and volcanic activity are therefore a fact of life in northeastern Africa, a fact that stems from the geographical location of that region: Ethiopia and the northern sector of the Horn of Africa border the main oceanic boundary between two major tectonic plates, the African and Arabian plates, and also straddle what has been recently termed "a failed rift" that marks the incipient 7 Stuttgart). Verlagsbuckhanlung, Schweizerbaresche the and authors the of permission by (reproduced 1975 al. et Kronberg after Africa, of Horn the and Ethiopia of Photomosaic ERTS-1. IA. Fig. 11 1 fr .. 1 _-.. 4 - ' N... .3 ' ir,,:,1 ,7 ' :4 4, 1 : , I v..-.1. , .1 -'4' tr.' b .f. t 9 .% L - , *., h II l pie., 4 . 41. ....it e . ... 4 ,L4 4:-'j. , ovri aL, * ' 9 A . w 7 f 4, . 1 t A y ,,,:, 34.4 r ; , I r. - .., , j,k,.,, , . , " k / ' . , . -.4. 4,14 .. - ' .;.- .r , ROSE G 8. GUNTHER R by Composed ( . , a k t. -.. i \ ... ' Km 2.90 100 7 SAND MSS 4 r REGIONS ADJACENT AND AFAR/ETHIOPIA THE OF ERTS-1-MOSAIC 00 breaking away of the East African minor continental plate from the rest of Aim and Scope of Monograph The contiguous major oceanic is iden- the African continent.