Joint ICPT / TWAS Workshop on Seismic Sources in Central America

What is the largest earthquake each can produce ?

Heredia, Costa RicaOctober 30 – November 5, 2011

Geological Studies for Surficial Faults Managua, Nicaragua

Marisol Echaverry L. & Antonio Álvarez C. Instituto Nicaragüense de Estudios Territoriales

Dirección General de GeofísicaDirección de Geología Aplicada

La Femina, 2002

Geological Setting Managua Area

BACKGROUNDS

31.03.1931Falla Estadio Centro Oeste

ManaguaRichter: 5.8Depth: 5Km

02.01.72Los Brasiles

16 Km. W ManaguaRichter: 5.5Mercalli: VI

23.12.1972Tiscapa Fault

Managua Lake Richter : 6.2Depth: 5 Km

Investigation of Active Faulting in Managua, Nicaragua and Vicinity Vice Ministerio de Planificación Urbana, Gobierno de la Republica de Nicaragua.

Woodward- Clyde Consultants. November de 1975.

Trench locationBefore, 80s

Morfological surficial expression

Exploratory trenches cartography

Disruption and

displacement key stratas

Managua Area

Geological Formations

Local Stratigraphy

Aligneaments and Faults

Age and Correlation

Map of Faults, 1975

BACKGROUNDS

DATA BASEDATA BASE

Analysis and integration of consultant reports. 1981 a 2002.Analysis and integration of consultant reports. 1981 a 2002.

Copies of 400 reports for library Copies of 400 reports for library

One hundred of lineal kilometers of trenchesOne hundred of lineal kilometers of trenches

Digitizing maps until 1981 (Brown et al., 1973)Digitizing maps until 1981 (Brown et al., 1973)

Woodward - Clyde Consultants, 1975 and Woodward - Clyde Consultants, 1975 and

Ministerio de la Vivienda y Asentamientos Humanos (MINVAH, Ministerio de la Vivienda y Asentamientos Humanos (MINVAH, 1981)1981)

2002 - THE INETER MAP OF FAULTS

BM / ASDI Proyects, BM / ASDI Proyects, 20012001

Objetives and scope

Find evidence of faults: active or not

Geological zoning of the land

Not build on faults

Guarantee the human life and prevent damages of properties

Inspection of Site Study for Soil Use Requirement

CONTENIDO : Proyecto Geologico Estructural

de las fallas activas en el area de Managua INETER/BANCO MUNDIAL/CEPREDENAC

LEVANTO : Gustavo Altamirano T.

DIBUJO : G. Altamirano Gonzalez

REVISO : Graziella Devoli

0.28 m

0.45

Corte de Falla Tiscapa -Pista Sub UrbanaUbicacion a 100mts al Este de la interseccion al centro de convenciones

Escoria Basaltica

Caida Vertical 0.34 mcaida lateral izquierdabuzamiento 42° NW Falla MayorFalla Tiscapa

(PHaq)

Escoria Basaltica

(Hsf) (PHaq)

(Hsf1 ) 0.70m

(Hsf) 0.6

0.55 m

Cesar Agusto Silva ( pared Sur) en la P ista

(Hfs1)Hsj

0.78 m

0.37 m

Hs0.18 m

Hfs 2

GAT 8-c

(Hs)4

3

2

1

0

0 5 10 15

(Haq)(Haq)

(Hsf1)

Escala IndicadaHoja Topografica San Judas

Pro

fundid

ad e

n m

etr

os

1975. Geological Method

Supervision of local geological studiesfor soil use requirements

2003. Método Geofísico

Inspection and Approval Process of the Study

Faults Map of Managua. March 2002, Escale 1:25,000

Distribución en el tiempo de estudios geológicos de falla local en Managua y alrededores Distribución en el tiempo de estudios geológicos de falla local en Managua y alrededores

Periodo 1990 a 2008. Fuente: Ineter, 2008Periodo 1990 a 2008. Fuente: Ineter, 2008

Estudios geológicos vs Tiempo

1990-2008: 1547 reports: 154.7 lineal Km2003 – 2008: Geological: 489

Geophysical: 32 2009 – 2011: 180 a 200

BOLETIN SISMOLBOLETIN SISMOLÓÓGICOGICO

CONCLUSIONS CONCLUSIONS

Datas about new fault sites, active or not, are available, and others could be Datas about new fault sites, active or not, are available, and others could be aggregates, but limited. No data about Neotectonics and Paleo seismology are aggregates, but limited. No data about Neotectonics and Paleo seismology are being colected.being colected.

know its seismical activity, above all, the most important faults is know its seismical activity, above all, the most important faults is necessary, and study that with no information but densely necessary, and study that with no information but densely inhabited. inhabited.

Could be practical and useful combine these geological studies with geodetics Could be practical and useful combine these geological studies with geodetics studies of deformation for prevention of seismic hazard and risk, for Managua studies of deformation for prevention of seismic hazard and risk, for Managua fault region and its vicinityfault region and its vicinity