GEOLOGICAL SURVEY CIRCULAR 925 

Earth and Water Resources and 

Hazards in Central America 

Earth and Water Resources and 

Hazards in Central America 

By Charles G. Cunningham, Raymond W. Fary, Jr., Marianne 

Guffanti, Della Laura, Michael P. Lee, Charles D. Masters, 

Ralph L. Miller, Ferdinand Quinones, Roger W. Peebles, 

John A. Reinemund, and David P. Russ 

GEOLOGICAL SURVEY CIRCULAR 925 

1984 
United States Department of the Interior 

WILLIAM P. CLARK, Secretary 

Geological Survey 

Dallas L. Peck, Director 

Library of Congress catalog-card No. 84-601007 

Free on application to Distribution Branch, Text Products Section, 

U.S. Geological Survey, 604 South Pickett Street, Alexandria, VA 22304 
CONTENTS 

Abstract ..................................................................................... . 

Introduction ............................................................................... . 

Background ------------------------------------------------------------------------

Purpose ............................................................................. . 

Sources of information and acknowledgments ........ ___ _ 

Geologic and hydrologic conditions, resources, and hazards 

in Central America ······································------------------

Geologic framework and evolution ................................. . 

Mineral resources and potential ....................................... . 

Known resources --------------------------------------------------------

Resource possibilities ............................................... . 

Energy resources and potential ....................................... . 

Oil and gas resources and exploration activity ....... . 

Coal resources and potential ................................... . 

Geothermal resources and potential ......................... . 

Water resources and hydrologic conditions ..................... . 

Geologic and hydrologic hazards .................................. . 

Status of earth and water resources in the Central American 

countries ....................................................................... . 

Belize ----------------------------------------------------------------------------------

Status of geologic and hydrologic information and 

programs ....................................... . 

Mineral resources and possibilities ........................... . 

Energy resources and possibilities ........................... . 

Water resources ............................................ __ ........... . 

Costa Rica ···············-···············-------------------------------------------

Status of geologic and hydrologic information and 

programs ....................................................... . 

Mineral resources and possibilities ........................... . 

Energy resources and possibilities ........................... . 

Water resources ......................................................... . 

Geologic and hydrologic hazards ............................. . 

Geothermal energy ...................... __ ........................... . 

El Salvador ............................................................... __ ...... . 

Status of geologic and hydrologic information and 

programs ....................................................... . 

Mineral resources and possibilities ........................... . 

Energy resources and possibilities ........................... . 

Water resources ......................................................... . 

Geologic and hydrologic hazards ............................. . 

Geothermal energy ................................................... . 

Page 

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5 

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21 

Status of earth and water resources in the Central American 

American countries~Continued 

Guatemala ......................................................................... . 

Status of geologic and hydrologic information and 

programs --------------------------------------------------------

Min era 1 resources and possibilities ........................... . 

Energy resources and possibilities. . .......................... . 

Water resources ......................................................... . 

Geologic and hydrologic hazards ------------------------------

Geothermal energy ----------------------------------------------------

Honduras------------------------------------------------------------················ 

Status of geologic and hydrologic information and 

programs ....................................................... . 

Mineral resources and possibilities ........................... . 

Energy resources and possibilities ........................... . 

Water resources ......................................................... . 

Geologic and hydrologic hazards ............................. . 

Geothermal enercy .................................................. . 

Nicaragua --------------------------------------------------------------------······ 

Status of geologic and hydrologic information and 

programs ....................................................... . 

Mineral resources and possibilities ........................... . 

Energy resources and possibilities ........................... . 

Water resources ......................................................... . 

Geologic and hydrologic hazards ............................. . 

Geothermal energy ................................................... . 

Panama ............................................................................. . 

Status of geologic and hydrologic information and 

programs ....................................................... . 

Mineral resources and possibilities ........................... . 

Energy resources and possibilities ........................... . 

Water resources ......................................................... . 

Geologic and hydrologic hazards ............................. . 

Geothermal energy ................................................... . 

Conclusions and recommendations ......................................... . 

References cited ......................................................................... . 

Appendix I. U.S. Geological Survey activities in Central 

America and bibliography of reports resulting from U.S. 

Geological Survey scientific and technical 

cooperation with Central American countries, 

1940-1983 ........................................................................ .. 

Appendix 2. Earth-scienee agencies in Central American 

countries .......................................................................... .. 

ILLUSTRATIONS 

Page 

21 

21 

22 

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23 

24 

24 

24 

25 

25 

26 

26 

26 

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27 

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Page 

FIGURE 1. Index map of Central America ------------------~----------------------------------------------------------------------------------------- 2 

2. Simplified tectonic map of Central America -----------------------·------------------------------------------------------------------ 4 

3. Map showing principal mineral and energy localities in Central America------------------------------------------------------- 6 

4. Graph showing rainfall distribution in Central America --------------------------------------------------------------------------- 11 

5-25. Maps showing: 

5. Major geologic divisions and principal mineral deposits in Belize ------------------------------------------------------------ 14 

6. Energy resource potential in Belize -------------------------------------------------------------------------------------------------- 15 

7. Major surface-water features of Belize -----------------------------~--------------------------------------------------------------- 16 

8. Major geologic divisions and principal mineral deposits in Costa Rica ----------------------------------------------------- 17 

9. Energy resource potential in Costa Rica ------------------------------------------------------------------------------------------- 18 

III 
FIGURE 5-25. Maps showing--Continued: Page 

10. Major surface-water features of Costa Rica ------------------------------------------------------------------------------------------ 19 

11. Major geologic divisions and principal mineral deposits in El Salvador -------------------------------------------------------- 20 

12. Energy resource potential in El Salvador ---------------------------------------------------------------------------------------------- 21 

13. Major surface-water features of El Salvador ------------------------------------------------------·---------------------------------- 21 

14. Major geologic divisions and principal mineral deposits in Guatemala--------------------------------------------------------- 22 

15. Energy resource potential in Guatemala ----------------------------------------------------------------------------------------------- 23 

16. Major surface-water features of Guatemala ------------------------------------------------------------------------------------------ 23 

17. Major geologic divisions and principal mineral deposits in Honduras ---------------------------------------------------------- 24 

18. Energy resource potential in Honduras ------------------------------------------------------------------------------------------------ 25 

19. Major surface-water features of Honduras ------------------------------------------------------------------------------------------- 26 

20. Major geologic divisions and principal mineral deposits in Nicaragua ---------------------------------------------------------- 27 

21. Energy resource potential in Nicaragua ------------------------------------------------------------------------------------------------ 28 

22. Major surface-water features of Nicaragua ------------------------------------------------------------------------------------------- 30 

23. Major geologic divisions and principal mineral deposits in Panama ------------------------------------------------------------- 31 

24. Energy resource potential in Panama--------------------------------------------------------------------------------------------------- 32 

25. Major surface-water features of Panama---------------------------------------------------------------------------------------------- 33 

TABLES 

Page 

TABLE 1. Mineral industry statistics for Central America ( 1981) ----------------------------------------------------------------------------- 7 

2. Central American world-class mines recently producing more than 150,000 t/yr of ore ------------------------------------ 7 

3. Metallic minerals produced in. Central America, 1977-1981 ----------------------------------------------------------------------- 8 

4. Metallic mineral elements in mineralized areas of the Central American countries ------------------------------------------ 8 

5. Most critical water issues in Central America ---=------------------------------------------------------------------------------------- 12 

6. Some specific water problems in Central America ----------------------------------------------------------------------------------- 12 

IV 
Earth and Water Resources and Hazards in 

Central America 

By Charles G. Cunningham, Raymond W. Fary, Jr., Marianne Guffanti, Della Laura, 

Michael P. Lee, Charles D. Masters, Ralph L. Miller, Ferdinand Quinones, 

Roger W. Peebles, John A. Reinemund, and David P. Russ 

ABSTRACT 

Long-range economic development in Central America will 

depend in large part on production of indigenous mineral, energy, and 

water resources and on mitigation of the disastrous effects of geologic 

and hydrologic hazards such as landslides, earthquakes, volcanic eruptions, and floods. The region has six world-class metal mines at present 

as well as additional evidence of widespread mineralization. Systematic 

investigations using modern mineral exploration techniques should 

reveal more mineral deposits suitable for development. Widespread 

evidence of lignite and geothermal resources suggests that intensive 

studies could identify producible energy sources in most Central American countries. Water supply and water quality vary greatly from 

country to country. Local problems of ground- and surface-water 

availability and of contamination create a need for systematic programs to provide better hydrologic data, capital improvements, and 

management. 

Disastrous earthquakes have destroyed or severely damaged 

many cities in Central America. Volcanic eruptions, landslides, mudflows, and floods have devastated most of the Pacific side of Central 

America at one time or another. A regional approach to earthquake, 

volcano, and flood-risk analysis and monitoring, using modern technology and concepts, would provide the facilities and means for acquiring knowledge necessary to reduce future losses. 

All Central American countries need to strengthen institutions 

and programs dealing with earth and water resources and natural 

hazards. Some of these needs may be satisfied through existing or 

pending projects and technical and economic assistance from U.S. or 

other sources. The need for a comprehensive study of the natural 

resources of Central America and the requirements for their development is evident. The U.S. Caribbean Basin Initiative offers both an 

excellent opportunity for a regional approach to these pervasive problems and an opportunity for international cooperation. 

INTRODUCTION 

BACKGROUND 

Economic well-being in Central America (fig. 1) 

has been of growing concern to the United States. 

Because of this concern, President Reagan has announced plans for a Caribbean Basin Initiative, 

which will provide a new approach to the economic 

development of the region. The program, approved 

by Congress, provides for free-trade guarantees and 

incentives and technical assistance. Much of the 

economic assistance will provide funds for imports 

essential to maintaining production and employment. The U.S. Agency for International Development (USAID) is using the remainder to support 120 

individual development projects. 

This current U.S. commitment to the Central 

American region is directed toward long-term 

economic development and a permanent increase in 

productivity and employment. In order to achieve 

these results, individual Central American countries 

need to inventory available indigenous resources and 

make effective use of those that can be developed. 

These resources, including land, energy, minerals, 

water, and people, must be used wisely for the 

development of agriculture, industry, and trade. Not 

only will gross national products increase, but the 

burden of expensive imports will also be eased. In addition, means should be found to minimize the 

devastating effects of the natural disasters-earthquakes, volcanic eruptions, landslides, floods, and 

waterborne diseases-that are prevalent in Central 

America. 

PURPOSE 

A logical way to stimulate long-term economic 

growth and to promote the general well-being in Central 

America would be ( 1) to define known natural resources, 

(2) to assess the potential for discovering additional 

resources, (3) to identify the risks of natural disasters, 

and ( 4) to evaluate the status of institutions and programs dealing with these subjects in the region. Information on the current status of resources, hazards, institutions, and programs provides a starting point for 

considering appropriate ways to increase productivity, 

trade, investment, and employment. 
' \ 

CARIBBEAN SEA 

\ N 

HONDURAS 0 200 400 Kilometers 

0 100 200 Miles 

NICARAGUA 

PACIFIC OCEAN 

FIGURE 1. -Index map of Central America. 
In recognition of the need for such information, the 

U.S. Geological Survey (USGS) has prepared this synopsis of the geologic and hydrologic framework-including mineral, energy, and water resources and geologic and hydrologic hazards-regionally and within 

individual Central American countries. It is hoped that 

the report will assist in formulating long-term development programs for the region. This synopsis is based in 

part on earth-science knowledge and experience acquired over more than 40years of USGS involvement 

in Central America, mostly through bilateral assistance projects, joint research, and multilateral programs. Appendix 1 summarizes USGS activities in Central America and includes a bibliography of reports 

resulting from activities from 1940 to 1983. 

This report also summarizes available information 

on the existing earth resources, institutions, and programs in Central America, including those with which 

the USGS is currently involved, and gives tentative projections of resource possibilities in the various countries. 

Appendix 2 lists names and addresses of agencies in 

Central American countries that deal with earth sciences 

and resources matters. Finally, this report focuses attention on the need for (1) current, reliable, good-quality, 

readily available resource information as a basis for 

encouraging capital investment, (2) regional efforts to 

mitigate the effects of geologic and hydrologic hazards, 

and (3) the importance of strengthening earth-science 

institutions and related programs. 

SOURCES OF INFORMATION AND ACKNOWLEDGMENTS 

Information and recommendations contained in 

this report are based in part on previous USGS investigations in Central America, in part on current activities and 

contacts, and in part on available published and unpublished materials from other sources. Recent compilations 

of regional geologic and resources information that have 

been especially valuable include a new geologic and tectonic map of Central America and the Caribbean region 

(Case and Holcombe, 1980), a new metallogenic map of 

North America (North American Metallogenic Map 

Committee,, 1981; Guild, 1981a, b), arrd new plate 

tectonic and geologic maps of the northeastern part of 

the Pacific and adjacent areas compiled by the CircumPacific Map Project, an activity of the Circum-Pacific 

Council for Energy and Mineral Resources(Drummond 

and others, 1981, 1983). For petroleum resources, data 

from Petro Consultants, Ltd., were essential. 

We thank the following people who helped to prepare this report by providing data and perceptive counsel: 

SimonM. Cargill, James E. Case, John H. DeYoung, Jr., 

Glenda F. Flowers, Kathie R. Fraser, Ennio V. Giusti, 

3 

Stephen E. Kesler, Richard D. Krushensky, Frank J. 

Sidlauskas, Jr., and Elizabeth J. Tinsley. 

GEOLOGIC AND HYDROLOGIC CONDITIONS, 

RESOURCES, AND HAZARDS IN 

CENTRAL AMERICA 

GEOLOGIC FRAMEWORK AND EVOLUTION 

Central America (Belize, Costa Rica, El Salvador, 

Guatemala, Honduras, Nicaragua, and Panama) consists 

mostly of a mountainous upland composed of a complex 

assemblage of rocks that accumulated over a period of 

several hundred million years. Geologic formations over 

much of the region are concealed by thick soil and dense 

forests, particularly on the slopes and lowland areas 

bordering the Caribbean Sea, where the tropical climate 

has produced dense jungle. Most of the population lives 

in the upland areas and in a narrow Pacific lowland belt. 

A chain of more than 80 active and dormant volcanoes 

reaches from the Mexican border to western Panama 

(fig. 2) along the Pacific side of Central America. Every 

country except Belize has some of this volcanic terrane. 

The topography and earth resources of Central 

America are directly related to the geologic history of the 

North and South American continents and the Caribbean 

basin. In the northwest, the rocks and geologic structures 

making up all of Guatemala, Honduras, El Salvador, 

and northwestern Nicaragua represent southeastward 

extensions of those found in Mexico. At the southeastern 

end of Central America, the part of Panama east of the 

Canal Zone is the western extension of the Andes Mountains of the South American continent. The gap between 

these continental extensions, some 900 km, includes 

southwestern Nicaragua, all of Costa Rica, and western 

Panama. The rocks here are formed by younger volcanic 

processes. 

The region now occupied by northern Central 

America was once a relatively shallow sea in which 

deposits of sand and mud accumulated and were later 

compacted to form sandstone, shale, and limestone. 

Some of these rocks were metamorphosed (recrystallized) 

by deep burial, compression, and heat. They are the 

oldest known rocks in Central America and are now 

exposed by erosion in much of Honduras, central Guatemala, and northern Nicaragua. U nmetamorphosed 

sedimentary rocks are exposed in large areas and 

numerous small basins mostly in northern Guatemala 

and Panama and in coastal lowlands generally bordering 

the Caribbean Sea. 

Beginning about 15 million years ago, an episode of 

volcanism, accompanied by earthquakes caused by 

strong compressive stresses, began to form a land bridge 
~ 

\ 

• • 

I 

SEA 

I 

. CARI,BE~N PLATE 

w 

.... 

<( 

PACIFIC • 

OCEAN 

~Jl,f 

eli1c~ 

COCOS PLATE 

EXPLANATION 

0 Volcanoes 

• Earthquake epicenters 

-Fault 

0 200 400 Kilometers 

0 100 200 Miles 

• • 

FIGURE 2. -Simplified tectonic map of Central America. 

..J 

a.. 

<( ~~· . "'\... (.) 

• 

-~:I: ·.• .... •:::) 

0 

CIJ 
between North and South America by pushing up the sea 

floor between the continents. This geologic activity, 

which continues to the present time, makes Central 

America one of the most active volcanic and seismic 

regions on Earth. The time at which the Central American gap was closed is not known precisely. 

The style of geologic evolution in Central America 

has resulted from the collision of large parts of the 

Earth's crust. The crust is broken into large, rigid segments or plates, which move extremely slowly but inexorably on a slowly deforming substratum. Where two 

plates collide, deformation and fracturing of the rocks 

take place and result in mountain-building and volcanic 

activity accompanied by earthquakes. In Central America, relative movement between theN orth American and 

the Caribbean plates is currently taking place along a 

fault crossing central Guatemala and extending eastward 

as the northern margin of the Caribbean basin (see fig. 2). 

In Guatemala, this fracture zone is called the Motagua 

fault; movement along this fault was the cause of the 

devastating 1976 earthquake in Guatemala. 

When an oceanic plate composed of heavy rocks 

collides with a continental plate of lighter rocks, the 

heavier oceanic plate is usually forced beneath the lighter 

continental plate. The displacement of one plate beneath 

another creates a trench in the sea floor such as the one 

along the Pacific margin of Central America. As their 

depth increases, oceanic rocks become intensely heated 

and form molten rock (magma). Some of this magma 

may move upward along fractures and erupt at the 

surface to form a volcano or chain of volcanoes. Such is 

the case along the western side of Central America, 

where the Cocos plate, consisting of oceanic rocks in the 

Pacific, has collided with the Caribbean plate and 

plunged beneath that plate to form the long line of active 

and dormant volcanoes along the Pacific coast. 

Locally, compression accompanyirtg the collision of 

two plates causes melting at depth of parts of the 

continental-type rocks. This melting forms magma, 

which moves upward into the overlying rocks and solidifies as intrusions of light-colored igneous rock called 

granite. The granite may contain economically important 

metallic elements such as gold, silver, tin, beryllium, and 

lithium. In other places, masses of dark-colored ultramafic rock formed from heavier constituents in a magma 

chamber may be mechanically emplaced on land or 

along linear vents in the sea floor. These masses may 

contain other economically important metallic elements 

such as nickel, chromium, and platinum. The geologic 

processes outlined above commonly lead to a complex 

distribution of rock types and to a variety of geologic 

structures. 5 

Rocks of the Central American countries can be 

grouped into the five major categories: (1) sedimentary 

rock (principally sandstone, shale, and limestone), (2) 

intrusive rock (granite and similar coarse-grained rock 

types), (3) volcanic rock (lava and ash), (4) ultramafic 

rock (peridotite, serpentine, and related rock types), 

and (5) metamorphic rock (schist, gneiss, quartzite, 

and other metamorphic rock types). Rocks in each 

category are potential hosts for specific mineral and 

energy resources and also have significance with regard 

to hydrologic, engineering, and land utilization 

capacities and problems. 

MINERAL RESOURCES AND POTENTIAL 

KNOWN RESOURCES 

Central America has produced gold, silver, nickel, 

aluminum, copper, zinc, lead, antimony, iron, mercury, 

manganese, tungsten, and cadmium(fig. 3, table 1). The 

region also contains other metals of economic interest, 

including chromium, cobalt, titanium, molybdenum, 

and tin. Construction materials and industrial minerals 

such as sand and gravel, limestone, gypsum, sulfur, barite, marl, diatomite, cement, and salt are produced, generally for domestic consumption. In spite of the diversity 

of minerals present, the mineral industry directly contributes less than 3 percent (and in most cases less than 1 

percent) to the gross domestic product of individual 

countries. Production of each mineral commodity is less 

than 1 percent of world production, with the exception 

of Guatemalan antimony, which has been about 1 percent (Martino and others, 1981). 

Although the mining industry has not been an 

important factor in any Central American economy 

(Grunwald and Musgrove, 1970; Martino and others, 

1981 ), the industry nevertheless has provided a continuing supply of exportable minerals and jobs at both large 

and small mines and support operations and might be 

expanded by the development of existing deposits and 

the discovery and development of new deposits. Development of existing large deposits and mines is related 

directly to world metal prices, labor costs, capital 

requirements, and interest rates. Development of small 

mines has certain advantages for less developed countries 

where unemployment rates are high in that it is labor 

intensive, requires less capital, takes advantage of small 

deposits, creates jobs in rural areas, and provides raw 

materials that can be used domestically (for example, 

construction materials and industrial minerals) or exported as a source of foreign exchange. A current overview of exploration and mining is given by W oakes and 

Carman ( 1983). 

Central America has six world-class mines whose 

recent ore production exceeds 150,000 tjyr (table 2). 
0'\ 

EXPLANATION 

x Coal localities 

•Au Principal mineral deposits 

*Petroleum development sites 

P4czpzc 

+ Operating geothermal powerplants 

CARIBBEAN SEA 

oce4N 

~ Geothermal sites under exploration or development 

~\ 

0 200 400 Kilometer~ 

0 100 200 Miles 

FIGURE 3. -Principal mineral and energy localities in Central America. Chemical symbols are identified in table 4. 
Country 

Belize -·----------------------

Costa Rica ________________ 

El Salvador ·-------------

Guatemala -----------·----

Honduras ----·-------------

Nicaragua ----------------

Panama -------------------· 

TABLE I.-Mineral industry statistics for Central America (1981) 

[Modified from Ensminger ( 1983). t, metric ton; bbl. barrel; oz, troy ounce; m3, cubic meter] 

Contribution to 

gross domestic 

Gross domestic product by 

product minerals industry 1981 mineral 

(1981 U.S. dollars) (percent) industry production 

121 million < l(?) Limestone, 479,700 t; marl, 548,900 t; sand and 

gravel, 589,300 t. 

4.7 billion <I Cement, 500,000 t; clay, 450 t; diatomite, 550 t; 

gold, 16,000 oz; lime, 7,000 t; salt, l, l 00 t; 

silver, l ,500 oz; crushed rock and rough 

stone, 550,000 m3; limestone, 50,000 t; sand 

and gravel, 200,000 mJ. 

3.4 billion <I Aluminum, 1 ,000 t; cement, 500,000 t; gold, 

1 ,000 oz; gypsum, 6,000 t; iron and steel, 

35,000 t; limestone, 500,000 t; salt, ~0.000 t; 

silver, 110,000 oz. 

3.15 billion "'1(?) Antimony, 510 t; barite, 5,200 t; cement, 

568,012 t; clay, 168,141 t; copper, 726 t; 

feldspar, 10,044 t; gypsum, 28,722 t; iron ore, 

4,025 t; lead, Ill t; lime, 24,655 t; nickel, 

5,000 t; crude petroleum, l ,800,000 bbl; 

pumice and ash, 20,451 t; salt, 13,679 t; 

silver, 8,000 oz; stone, sand, and gravel, 

2,390,000 t; zinc, 2,996 t. 

2.7 billion 2.5 Antimony, 20 t; cadmium, 200 t; cement, 

500,000 t; copper, 250 t; gold, 3,000 oz; 

gypsum, 20,000 t; iron and steel, 20,000 t; 

lead, 14,000 t; salt, 30,000 t; silver, 2,400,000 

oz; limestone and marble, 500,000 t; zinc, 

18,000 t. 

2.9 billion <I Cement, 100,000 t; gold, 70,000 oz; gypsum and 

anhydrite, 30,000 t; lime, 30,000 t; salt, 

18,000 t; silver, 167,000 oz. 

3.8 billion "'1(?) Cement, 600,000 t; clay 99,624 t; salt, 15,000 t; 

stone, sand, and gravel, 2,560,000 t. 

Remarks 

No metallic minerals produced 

in 1981. Oil exploration but 

no production. 

Major gold mine. Hydroelectric 

generating capacity to be 

increased. High priority to 

develop energy sources. Active coal assessment program. 

Aggressive geothermal development program. Hydrocarbon 

production small. 

Major nickel plant recently 

closed. Major copper mine. 

Exports oil. 

Exports precious and base 

metals from major preciousand base-metal mine. New 

cement plant. Increasing hydroelectric generating capacity. Oil exploration active. 

Major gold mines. Limited 

petroleum exploration. 

Major copper deposits 

However, detailed descriptions and production information about smaller mining operations are not consistently published. Salas (1982, p. 189) reports that, in 

Latin American countries, there are many small-scale 

mining operations ofless than 60,000 t I yr; in Mexico, for 

example, small mines account for more than 20 percent 

of total annual production. 

TABLE 2.-Central American world-class mines recently producing 

more than 150,000 tlyr of ore 

Five countries (Costa Rica, El Salvador, Guatemala, 

Honduras, and Nicaragua) have produced most of the 

metallic minerals in Central America during the period 

1977 to 1981 (table 3); all seven Central American countries have produced construction materials during the 

same period. Metallic mineral production has been 

inhibited in Central America (and elsewhere) by fluctuating metal prices, uncertainty about resource adequacy, world inflation, and rising energy costs. 

7 

[Modified from Mining Magazine (1983)] 

Country 

Production (1,000 tjyr) 

and mine 150-300 300-500 500-1,000 Commodity 

Costa Rica, Santa ---------· X Gold 

Clara 

Guatemala, Oxec -·---------- X 

Honduras, El ------------------

Mochito 

Nicaragua: 

Senten trion 

Siuna ------·----------·--------

X 

Vesubio ---------------------- X 

Copper 

X Zinc, lead, 

copper, gold, 

silver. 

Gold 

X Gold 

Zinc, lead, 

copper, gold, 

silver. 
TABLE 3.-Meta/lic minerals produced in Central America, 1977-1981 

(From Ensminger ( 1983). Production values represent mine output. No metallic mineral production is reported for Belize and Panama during the period 1977 to 1981. . production data 

for some countries and commodities for years indicated have not been available. Metal contents of ores and concentrates are in metric tons. unless otherwise noted] 

Antimony ······------------------------------

Cadmium ------------------------------------

Copper --------------------------------------·-

Gold1 ----------------·-----------------------·-

Iron2 ------------------·-------------------------

Lead-·-------------···--------------·----------

Nickel _________________________________________ _ 

Silveri--·-----·-·-----------·------·------------

Tungsten -----------------------·---------·--

Zinc -------------------------------·---------·--

IJn troy ounces. 

21 ron-ore tonnage. 

Costa Rica El Salvador 

77,000 12,000 

8,000 700,000 

3Small but undetermined quantity contained in zinc concentrates. 

Development of the mineral industry in Central 

America has also been inhibited by the economic and 

political instability of the region. 

A variety of metallic minerals is present throughout 

Central America, but many have not been produced. 

Table 4 shows the distribution by country of metallic 

elements in mineral deposits, as depicted on the Metallogenic Map ofN orth America (North American Metallogenic Map Committee, 1981). Often, more than one 

metal is present in a deposit. The table shows that precious metals have been found in every country, whereas 

other commodities such as tin, chromium, and nickel 

Guatemala 

2,900 

7,900 

18,000 

440 

19,000 

38,000 

50 

7,000 

Honduras 

240 

1.200 

3,000 

12,000 

88,000 

12,000 

110,000 

Nicaragua 

400 

330,000 

37 

1,400 

1,400,000 

14,000 

have been found in only a few, probably because even 

small precious-metal deposits are highly profitable and 

are sought under the most difficult circumstances. 

Although one mineral commodity (gold) has been 

mined in Central America since the 12th century, detailed 

knowledge of the geology and mineral resources of the 

region is sparse. Many deposits may be concealed by 

deeply weathered soil, dense tropical rain forests, or large 

areas covered by young, noneconomic sediments and 

volcanic rock. Nevertheless, a large part of Central 

America is known to be geologically similar to the 

mineral-rich Sierra Madre Occidental region of Mexico. 

TABLE 4.-Meta/lic mineral elements in mineralized areas of the Central American countries 

[From Guild ( 1981 a. b). Several metallic mineral elements are often reported from a single mineral deposit.--, no data] 

Gold (Au) ------------------------------

Silver (Ag) ------------------------------ Copper (Cu) _________________________ _ 

Lead (Pb) --------------------------------

Zinc (Zn) --------------------------------

Iron (Fe) --------------------------------

Titanium (Ti) -·---·---·-·--------------

Aluminum (AI) --------------·-----·-

Manganese (Mn) ___________________ _ 

Molybdenum (Mo) ·---·-·-·---·-·-

Antimony (Sb) _____________________ _ 

Cadmium (Cd) _____________________ _ 

Cobalt (Co) ___________________________ _ 

Chromium (Cr) ·---------------------

l"ickel (Ni) ----·---·-·-····--------------

Tungsten (W) _________________________ _ 

Mercury (Hg) -----·------------------

Tin (Sn) ---------------·------------------

Belize Costa Rica 

5 

3 

4 

6 

6 

5 

4 

El Salvador Guatemala Honduras 

6 2 24 

6 7 15 

2 3 

8 3 

8 4 

2 

2 

2 

2 

8 

Nicaragua Panama Total 

21 20 79 

8 I 40 

3 8 21 

2 21 

2 21 

3 12 

6 

4 5 

2 3 

2 3 

3 

2 

2 

2 

2 

2 
A comparison of the number and types of mineral deposits of these two regions indicates that Central America 

should have additional mineral deposits and mineral 

commodities that could be developed. 

Rocks and ore deposits of Central America are 

products of an active tectonic regime. The northern part 

of Central America is composed of large areas of relatively old igneous and metamorphic rocks, which contain 

deposits of silver, lead, antimony, mercury, and tin. The 

Motagua fault zone contains ultramafic rocks that originated several kilometers deep in the earth, along with 

associated deposits of nickel, chromium, and cobalt. 

Volcanic rocks that parallel the Pacific coast contain 

mineralized veins of gold, silver, lead, and zinc. Farther 

south, other volcanic rocks contain deposits of manganese. Some volcanic rocks are cut by intrusive rocks 

containing deposits of copper and molybdenum. Precious-metal deposits also occur in some places where 

sedimentary rocks have been intruded by igneous rocks. 

Mineral deposits in Central America tend to contain 

more silver and lead in the north and more gold and 

copper in the south. 

RESOURCE POSSIBILITIES 

Increasing the level of geologic knowledge about 

Central America should lead to the discovery of additional mineral resources. Concepts and technologies of 

mineral-resource evaluation, as well as those of the oreforming processes, have evolved greatly in the past 

decade (Skinner, 1981). They can be applied to explore 

beneath the cover of young rocks and thick soil to find 

concealed deposits. Strategic and critical minerals, including the platinum-group minerals, and other metals 

such as gold, titanium, and the rare-earth elements may 

exist in heretofore unexplored geologic terranes. These 

terranes should be examined with modern exploration 

techniques, and the results should be evaluated in the 

light of recent concepts about ore-forming processes. 

In Central America, as elsewhere, the types of rocks 

present and their geologic settings determine the kinds of 

mineral deposits (and thus the kinds of commodities) 

that may be present. By comparing the various geologic 

terranes in Central America with similar terranes elsewhere, applying the curent knowledge of geologic processes, and employing ore-deposit models (Erickson, 

1982), one can make an estimate of the kinds and, in 

some cases, the amounts of metallic minerals that would 

reasonably be expected to be present. 

One of the largest open-pit gold deposits in the 

western hemisphere (Pueblo Viejo in the Dominican 

Republic) was formed in volcanic rocks similar to those 

existing in Central America. Massive sulfide deposits 

9 

containing zinc, lead, copper, gold, silver, and manganese deposits like those found in Cuba may exist in 

similar geologic terranes that are now covered by younger 

sedimentary and volcanic rocks. Phosphate deposits like 

those being mined in Florida are expected to be present 

but may be unrecognized because of the deeply weathered 

rock and thick soil. Heavy-metal-bearing sands containing platinum minerals (like those in Colombia), gold, tin, 

and rare-earth elements might be present in buried offshore beaches. Cobalt and tin are known to be present in 

Central America, but there is no information on the 

geologic environment of their occurrence. U nconventional mineral resources should not be overlooked; these 

include various metals in black shales, uranium in phosphate, various metals in coals, or byproducts of mining 

operations. 

ENERGY RESOURCES AND POTENTIAL 

OIL AND GAS RESOURCES AND EXPLORATION ACTIVITY 

Geologic conditions in Central America are only 

marginally favorable for petroleum occurrences. Favorable areas are confined to those parts of the region that 

have adequate thicknesses of sedimentary rock and that 

contain favorable source and reservoir rocks. Oil and gas 

originate as products of the natural chemical alteration 

of organic materials. For a province to contain recoverable petroleum resources, those original organic materials 

must have been deposited in a poorly oxygenated environment and buried deeply enough for Earth temperatures to have fostered the chemical reactions necessary to 

form petroleum. Furthermore, once the petroleum had 

attained a liquid state, it must then have been able to 

migrate from the source rocks to a collecting area having 

reservoir properties favorable for accumulation and 

large enough for economic recovery. Thus, to have 

become petroleum producing, an area must have possessed source rocks, reservoir rocks, and geologic traps. 

Because migration of the oil from the source area to a 

reservoir is required, the time of formation of the trap 

and reservoir must have preceded that of the maturation 

of the organic matter and its subsequent migration into 

the reservoir as liquid petroleum. 

For the Central American region as a whole, the 

most important limitation to petroleum development 

appears to be a lack of the geologic conditions necessary 

for the formation of suitable reservoirs. Information 

leading to this judgment has been derived from the several tens of wells drilled throughout the region, but not 

enough drilling has been done to be conclusive. The 

drilling has, however, provided considerable data on the 

maturity of potential source rocks. In many areas having 
sedimentary rock, the underground temperatures, down 

to drilling depths that are presently economically reasonable, have not been high enough to convert the organic matter to oil or gas. Information available at this 

stage of exploration in certain areas is therefore 

somewhat discouraging, but the continued and recent 

concession-taking and exploration activity conducted 

in most of the Central American countries by U.S. oil 

companies and those of other nations suggest that the 

region still holds potential for the discovery of 

economic oilfields (Deal, 1982). 

Areas that might contain oil and gas resources are 

outlined on figures accompanying individual country 

descriptions; the seaward limiting boundary of economic 

operations has been set arbitrarily at the 200-m (650ft) 

isobath. To date, commercial accumulations have been 

identified only in Guatemala. Shows of oil and gas, 

however, have been reported in the Limon Basin of 

Costa Rica near the Panamanian border on the Caribbean side and also offshore from Nicaragua where thick 

sedimentary rocks compose the Nicaragua Rise. 

COAL RESOURCES AND POTENTIAL 

Coal has been known in Central America since 

1860, when a U.S. Navy expedition to Panama recorded 

several lignite beds of minable thickness on the northern 

coast. Since then, national agencies have accumulated 

resource data demonstrating the presence of coal, including lignite, in every Central American country except 

Belize. As energy needs expanded in these developing 

countries during this century, demands were met largely 

by inexpensive imported oil. As a result, although more 

reports of coal have become known, no substantive effort 

has been made to study the.potential for coal exploitation 

until very recently, when the cost of imported oil increased dramatically. Several Central American countries are now considering coal as an alternative source of 

energy and are starting programs to determine if any of 

their coal deposits are of sufficient quality and quantity 

to merit exploration and development. 

In most localities, the number of coal beds is 

unknown, but 11 beds are reported at one locality in 

Guatemala, and 8 are reported at one locality in Panama. 

The sulfur and ash contents are also generally unknown, 

but reported values range from low (<I percent) to high 

(> 15 percent) for sulfur and medium (>8 percent) to high 

(> 15 percent) for ash. None of the Central American coal 

deposits is known to contain coal of high enough rank to 

qualify as coking coal. 

A preliminary unpublished estimate of Central 

American coal resources made by G. H. Wood, Jr., of the 

USGS totals 355 million short tons (identified and hypo10 

thetical). This figure is, however, considered to be minimal because no data are available on which to base an 

estimate for many of the reported localities. 

Lignite, which constitutes most oft he reported coal 

deposits in Central America, is not the most desirable of 

fuels, yet it is used in many parts of the world, especially 

for the production of electricity. Until the results of 

preliminary investigations into numerous reports of coal 

occurrences in Central America are available, it is not 

possible to predict how viable a substitute for petroleum 

the coal deposits of the region may be. Bohnen berger and 

Dengo ( 1978) have concluded __ "a systematic campaign 

to evaluate the carbonaceous beds of Central America 

should be carried out. ... The results of such a program 

would be extremely valuable for a regional evaluation." 

In light of the many known coal occurrences and given 

the possibility of additional unknown occurrences, it 

would indeed be surprising if at least a few of these 

deposits did not prove to be exploitable. The known 

occurrences of coal are shown on individual country 

maps. In addition, new technology is proving that the 

conversion of peat to methanol (a form of alcohoD for 

the generation of energy is economically viable. There 

has been no interest in and no exploration for peat 

deposits in Central America to date, but it is very probable that peat deposits exist. 

GEOTHERMAL RESOURCES AND POTENTIAL 

Central America is ideally situated with regard to 

geothermal energy potential. Despite its relatively small 

geographic extent, the region contains active segments of 

five major tectonic plates. Young volcanic centers concentrated along zones where these shifting plates abut 

against or grind slowly past one another provide deep 

heat sources for overlying geothermal systems. Thus, the 

region's numerous volcanic centers present prospective 

target areas for geothermal exploration and development. 

Emphasis on the development of geothermal energy 

in Central America probably will continue to concentnite on electric power generation rather than nonelectric 

direct uses. Several geothermal fields capable of supporting electrical generating plants have already been identified, and many other undiscovered systems undoubtedly 

exist. Development of these geothermal resources for 

electrical generation, in conjunction with the development of other indigenous energy resources, may significantly decrease Central America's dependence on imported oil. Presently, El Salvador's 95-MW geothermal 

plant produces about 25 to 44 percent of the country's 

electricity, and Nicaragua's newly opened 35-MW plant 

provides 12 percent of its electricity. 
Nearly every country in the region has conducted 

geothermal exploration programs. In addition, the Latin 

America Energy Organization has sponsored major conferences on geothermal exploration since the late 1970's 

and has carried out major reconnaissance and predevelopment feasibility studies. Some of the more developed 

countries (for example, the United States, Japan, Italy, 

Iceland, France, Great Britain, and New Zealand) have 

participated in these conferences and (or) provided funding and technical assistance for development programs. 

WATER RESOURCES AND HYDROLOGIC CONDITIONS 

Precipitation throughout Central America ranges 

from 500 to 7,500 mmjyr (20-295 in.jyr), the average 

being 2,500 mm (100 in.). Yearly totals range widely 

from place to place; drier coastal areas receive less than 

500 mm (20 in.), and the wet interior mountains receive 

as much as 7,500 mm (295 in.). The region has pronounced wet and dry seasons (fig. 4). From May to 

October, rainfall is abundant; January, February, and 

March are dry. Because of the easterly trade-wind flow, 

the Caribbean coast and the east-facing slopes of mountains receive the heaviest rain. Caribbean hurricanes are 

a threat to the region from Costa Rica northward. Pacific 

hurricanes are less of a threat because they generally turn 

north before reaching the western coast. 

Water supply for basic human needs is without 

question the most severe water problem in Central 

America. Problems exist in both urban and rural areas. 

Waterborne diseases are the greatest killer, and dysentery 

is the major cause of infant mortality. Contamination of 

J F M A M 

surface-water supplies is widespread, and there are cases 

of deterioration in the quality of ground-water supplies 

(United Nations, 1976). These conditions are frequently 

aggravated by drought. 

Despite the abundance of rain over most of the 

region, water availability is a frequent problem (United 

Nations Educational, Scientific, and Cultural Organization, 1982; Bulkley and others, 1965). Natural 

variability in the yearly rainfall cycle can have strong 

impact on rainfed agriculture. For example, a delay in 

the onset of the rainy season in Hone uras almost 

always brings severe drought to the south and west 

(U.S. Agency for International Development, 1982). 

There is good potential throughout the region for 

alleviating the impact of surface- and ground-water 

resources (Patchick, 1968). 

Extensive clearing of tropical forests for grazing 

lands has resulted in severe erosion and flooding problems. The dense vegetation and tropical climate result in 

high evaporation rates throughout the year. Because 

watersheds are small, drought conditions can occur during even moderately extended dry seasons and cause 

severe disruption in water supplies for domestic, industrial, and agricultural areas. These problems are aggravated by infrastructure deficiencies and lack of capital 

for investment in structures and nonstructural solutions. 

Water is also necessary to support mining operations. However, mining often reduces the quality of the 

water used either directly (for example, in washing operations) or indirectly (for example, natural seepage from 

tailings exposed to the atmosphere may result in pollution of both ground and surface water). 

J J A S 0 N D 

Belize 

Costa Rica 

El Salvador 

Honduras 

Guatemala 

Nicaragua 

Panama 

••••• ·····-----------------------········· 

.... ·-----------------........ . ..... -----------------------------· ... .... ·-----------------------.... .... ·------------------· ....... . .... ·------------------· ....... . 

- Rainy season 

••••• Scattered rain 

Dry 

.... ·------------.... 

FIGURE 4.-Rainfall distribution in Central America. The Carib bean coast generally receives heavier annual rainfall owing to 

the prevalence of the easterly trade winds. Rain shadows generally occur on the western slopes of the high mountain ranges. 

11 
Industrial water needs will continue to grow as 

capital investments are made in the region. Waterconservation measures will need to be introduced simultaneously to prevent adverse impacts on current water 

supplies (United Nations Development Program, 1981 ). 

The mountainous topography and abundant rainfall of Central America provide an excellent setting for 

hydropower development. A number of countries in the 

region have developed hydropower resources that supply 

the major portion of their electric power needs. Much 

potential is reported (U.S. Agency for International 

Development, 1982), but development should proceed 

only after careful study of regional water-resources 

availability, particularly with regard to the magnitude 

and variability of river flows and sediment loads. 

A strong need exists for basic data on streamflow 

and sediment-discharge and rainfall-runoff relationships; 

these data will lead to programs for minimizing adverse 

effects and maximizing beneficial impacts, particularly 

with regard to flood control, reservoir management, and 

hydropower development. 

The most critical water issues for Central America 

are shown in table 5, and some specific water problems 

are shown in table 6. The conclusion to be drawn about 

hydrologic conditions in these tropical countries is that 

the typical spectrum of water-resources problems exists; 

the challenge is to solve these problems through assessment and wise capital investment. 

GEOLOGIC AND HYDROLOGIC HAZARDS 

The many earthquakes and volcanic eruptions that 

occur in Central America produce geologic hazards that 

are a constant and significant problem for a substantial 

percentage of the population. Most of the destructive 

earthquakes occur in topographic depressions that lie 

along the general trend of the volcanoes, in depressions 

formed by transverse breaks in the volcano trend, or in 

river valleys that follow major plate-bounding faults (fig. 

2). All of these areas are also the sites of major population 

centers. The great damage and loss oflife caused by these 

earthquakes are directly attributable to their shallow 

focus, their location in areas of low relief where cities are 

commonly situated, and their subsequent triggering of 

massive landslides. More than 80 active or geologically 

young volcanoes are concentrated in a 600-km-long belt 

that extends nearly the length of Central America. These 

volcanic centers provide sources of deep heat for overlying geothermal systems, but potential future eruptions 

pose hazards to nearby communities and geothermal 

installations. 

TABLE 5. -Most critical water issues in Central America 

HAZARDOUS WATER PROBLEMS 

1. Flooding 

2. Droughts 

3. Landslides and mudslides 

4. Hurricanes 

WATER PROBLEMS 

1. Poor surface-water quality 

2. Poor ground-water quality 

3. Limited ground-water resources 

4. Water logging 

WATER FOR DEVELOPMENT 

1. Domestic supply and sanitation 

2. Hydropower 

3. Agriculture (food and fiber) 

4. Mining 

5. Navigation 

BASIC SUPPORT NEEDS 

1. Specialized expertise 

2. Equipment 

3. Funds for operation and maintenance 

4. Infrastructure and institution building 

5. High tech 

TABLE 6.-Some specific water problems in Central America 

[Data from United Nat ions ( 1980)] 

Belize Costa Rica El Salvador Guatemala Honduras Nicaragua Panama 

Flooding............................................................ X X X X X X 

Droughts ......................................................... . X X X X X X 

Surface-water and ground-water .................... X X X X X X X 

contamination. 

Erosion and sedimentation .............................. X X X X X X X 

Poor natural ground-water quality. ................ X X 

Ground-water quantity limited ....................... . X X X X 

by geology. 

Aquifers overdeveloped ... .. .. .. .. . . ..... ...... .. .. .. .. .. .. X X X X X X X 

Saline water encroachment ............................ . X X X X 

Waterlogged land ..... .. .. .... ......... .. ...... .............. .. X X X 

12 
Floods cause severe damage throughout the region. 

Their major causes are hurricanes and heavy rains associated with tropical disturbances that move onshore 

from the Caribbean. In areas that have been deforested, 

floods are especially severe and are accompanied by 

destructive erosion and, in some cases, by earth flows 

and mudslides. Because rainfall is variable, the region is 

also subject to frequent drought. As recently as May 

1983, Tegucigalpa, the capital of Honduras, was suffering from an acute water shortage caused by a delay in the 

onset of the rainy season. 

Clearly, geologic and hydrologic hazards are natural 

and continuing phenomena that man must study, understand, and prepare for if he wishes to live and prosper in 

Central America. 

STATUS OF EARTH AND WATER RESOURCES 

IN THE CENTRAL AMERICAN COUNTRIES 

BELIZE 

STATUS OF GEOLOGIC AND HYDROLOGIC 

INFORMATION AND PROGRAMS 

Detailed geologic maps of Belize do not exist, but 

generalized geologic maps are available (Bonis and others, 1970; Case and Holcombe, 1980). Generally flatlying, unmetamorphosed sedimentary rocks extend south 

and east from Mexico and Guatemala and cover about 

80 percent of Belize. The Maya Mountains, located near 

the middle of the country, are composed of older metamorphic, intrusive, and volcanic rocks. Little information is available on mining or mineral exploration in 

Belize, and mineral production appears to have been 

limited to building materials, sand and gravel, limestone, 

and marL No hydrologic maps of the country have been 

published. 

MINERAL RESOURCES AND POSSIBILITIES 

Geologic exploration and mapping of Belize appear 

to have been discouraged by the lack of a mining history 

and by dense tropical jungle. Occurrences of gold, tin, 

copper, lead, zinc, and barite have, however, been 

reported (Bateson and Hall, 1977; Guild, 1981 a, b; Weyl, 

1980). Belize is the only Central American country to 

have a reported occurrence of tin (fig. 5). Molybdenum, 

lithium, beryllium, and tungsten typically occur with tin, 

and this association should be examined. 

ENERGY RESOURCES AND POSSIBILITIES 

Oil seeps have been reported, and an offshore test 

well reported shows of oil in 1981. There is no oil production at present; however, three U.S. companies have done 

drilling or surface exploration in Belize as recently as 

13 

1981, and two wells were drilled in 1982. In 1982, there 

were 24,838 km2 held under lease. Sedimentary formations in Belize are eastern extensions of those of the 

Chapayal-Peten Basin of Guatemala, where two small 

fields have produced oil since 1974 and 1977. This fact, 

combined with the knowledge that the Mexican part of 

this same general geologic province contains the prolific 

Reforma district (in a different geologic setting), encourages continued onshore and offshore exploration. 

Belize is the only Central American country in 

which coal or lignite has not been reported (fig. 6), 

possibly because of a lack of exploratory efforts. It is 

possible that coal or lignite may occur in the extreme 

south of Belize in formations corresponding to those 

reported to be coal bearing nearby in Guatemala. 

Because Belize is remote from the belt of young Central 

American volcanoes, high-temperature geothermal resources are less likely to be discovered. 

WATER RESOURCES 

Belize, like most countries in Central America, has 

abundant water resources. The subtropical climate of 

Belize is affected by its topography and seasonal trade 

winds from the Caribbean. Precipitation varies geographically from about 1,300 mmjyr(51 in.jyr) at Corozal 

along the coastal plains to as much as 4,450 mm/ yr ( 175 

in.jyr) at Feleko in the Mayan Mountains. Precipitation 

also varies seasonally, as much as 80 percent of the annual 

total occurring from June to October. The principal 

rivers in the country (fig. 7) are the Hondo, the 

New, and the Belize, which is navigable in its lower 

reaches. These rivers and others offer untapped 

hydroelectric potential. 

The main hydrologic problems in Belize are related 

to hurricanes, water supply, water quality, and overall 

water-resources management. Hurricanes affect Belize 

frequently (six since 1931), causing severe damage and 

extensive flooding. Less than 50 percent of all households in the country are connected to potable water 

supplies. Lack of sewerage facilities results in discharge 

of wastes to streams and consequent contamination of 

surface and ground water. The quality of ground water is 

also affected in some areas by high concentrations of 

sulfate and calcium-magnesium, which increase hardness. 

The country needs funds for equipment and training 

of personnel to conduct in-depth water-resources investigations. 

COSTA RICA 

STATUS OF GEOLOGIC AND HYDROLOGIC 

INFORMATION AND PROGRAMS 

Although geologic maps and information for Costa 

Rica are more extensive than those for some other Cen-
...... 

..j::. 

88° 

18° ~ L:··.;.-.;:···:·:--.-·-1 ll( 18° 

Vj ~ Sn (Mountain Pine 

Ridge deposit) ~ ::r;: 

n Creek ~ 

~ ~ Au (Quebrada Ceibo ~///~ 

Grande deposit) u 

1: .:.-.r 1 16 o 

88° 

EXPLANATION 

~ 

~ 

Sedimen~a~y rocks 

and surf1c1al cover 

Intrusive rocks 

(mostly granites) 

~Metamorphic rocks 

0 100 200 Kilometers 

I I I I I I I 

0 50 100 Miles 

FIGURE 5. - M ajar geologic divisions and principal mineral deposits in Belize. Geology simplified from Case and H alcorn be ( 1980). The metals 

contained in deposits are indicated by chemical symbols. Locality names are in parentheses. 
EXPLANATION 

M Area of possible petroleum occurrence 

0 

I 

0 

I 

50 

100 

I I 

200 Kilometers 

I 

100 Miles 

FIGURE 6.-Energy resource potential in Belize. The seaward boundary is defined by the 200-m isobath. 

tral American countries (Weyl, 1980, p. 324-329), the 

most recent known compilation was made in 1968 

(Dondoli and others, 1968). Volcanic rocks of both continental and marine origin occupy about half of northern 

Costa Rica, which is dominated by the active volcanoes 

Irazu, Poas, and Turrialba. These volcanic rocks overlie 

or are interbedded with sedimentary strata, mostly of 

marine origin, which crop out over most oft he southern 

part of the country. Granitic rock bodies are present 

along the axis of the southern mountain region of the 

country, and one ultramafic body has been reported 

along the Pacific coast. 

MINERAL RESOURCES AND POSSIBILITIES 

Gold is the principal metal produced in Costa Rica, 

but various industrial minerals and construction materials are also mined (see table 1). The Santa Clara openpit gold mine (fig. 8) is ranked world class (Mining 

Magazine, 1983). Silver, lead, and zinc ore deposits are 

reported in close proximity to some gold deposits. 

Undeveloped deposits of aluminum, copper, manganese, 

and iron- and titanium-bearing sands have also been 

reported. 

15 

It seems likely that additional deposits of gold, 

silver, copper, lead, zinc, and other metals may be discovered if more extensive mapping and geochemical and 

geophysical surveys are carried out, especially in the 

northwest and south. The ultramafic rocks should be 

evaluated for nickel, chromium, and platinum-group 

mineral content. Possibilities for phosphate should also 

be investigated in the sedimentary rock sequences, especially in those of Cretaceous age, which have showings 

of phosphate in Nicaragua. 

ENERGY RESOURCES AND POSSIBILITIES 

Although oil and gas have not yet been found in 

economic quantities in Costa Rica, producible amounts 

may exist on both sides of the country. On the Caribbean 

side, the Limon Basin, which appears to be a southward 

extension of the Nicaragua Rise, has showings of oil at 

depths of I ,220 to I ,520 m (3,880 to 4,840 ft) in holes 

drilled onshore. The most favorable region, judging by 

the amount of industry exploration, appears to be near 

the Panamauian border. On the Pacific side of the country, where a narrow offshore basin exists, applications 

for concessions have been submitted, but no records of 
0 

I 

0 

I 

50 

100 

I 

I 

200 Kilometers 

I 

100 Miles 

FIGURE 7. -Major surface-water features of Belize. 

16 
...... 

-.l 

S6° 

M n (Peninsula 

de Nicoya 

CARIBBEAN 

SEA 

EXPLANATION 

~ s;~~r:~~;i~~~~r~~~=r c "· • ·' · • ' Intrusive rocks 

(mostly granites) 

deposits) ~ . ·::~ .. r1:#i:J~> ;-;:·::·.-.-.·.:·-·.·._:>:t\Imon 10 o 

0 I "' .. !?\ .. ~i .. , !{ ........ . 10 ~~ ··.. L • v • •• • • • n __ ..~_ l"' --- ---- n A ~T·A_·n..f;:.·.:·."·.'-;. Volcanic rocks 

S6° 

Au,Ag (Santa Clara mine) 

Au,Ag (Esparata district 

Ag,Pb,Zn (Aguacate district 

p 

;.;JC?~ 7c 

so ~ so 

S4° 

Ultramafic rocks 

0 100 200 Kilometers 

0 50 100 Miles 

FIGURE 8. -Major geologic divisions and principal mineral deposits in Costa Rica. Geology simplified from Case and Holcombe ( 1980). The 

metals contained in deposits are indicated by chemical symbols. Locality names are in parentheses. 
exploration have been reported. Relatively high heat 

flow in that area enhances the potential for petroleum. 

Coal has been reported at a number of localities in 

Costa Rica (fig. 9). One of these localities is the Volio 

deposit in the east-central corner of the country, about 3 

mi from the Panamanian border. A project to explore 

and appraise this deposit is in the planning stages; USGS 

and the Bechtel Corporation will provide assistance, 

under the auspices of USAID. Results of preliminary 

investigations are encouraging, but detailed mapping, 

drilling, sampling, and analysis of the coal beds will be 

needed to resolve the complex geologic structure and to 

determine the minable reserves. The coal that occurs in 

the V olio deposit is in beds 1 to 2 m thick and appears to 

be sub bituminous and of good quality. Other coal localities have not been examined sufficiently to determine 

whether similar exploration and appraisal programs 

would be warranted. 

WATER RESOURCES 

The climate and hydrology of Costa Rica vary 

across its three distinct physiographic regions (the 

Caribbean watershed, the Central Mountains, and the 

Pacific watershed). Precipitation varies _from ab()Ut 

1,300 mm/yr (50 in./yr) on the coast to as much 

as 7,500 mmjyr (295 in.jyr) in the Central Mountain 

Range. Although hurricanes rarely affect the country, 

monsoon rains cause frequent damaging floods (three 

Miravalles geothermal field 

major floods since 1970). Rivers abound throughout 

Costa Rica (fig. 10), the principal ones being the San 

Juan, the Tempisque, and the Sixaola (U.S. Army Corps 

of Engineers, 1965). 

Ninety-eight percent of the electric power presently 

generated in Costa Rica is hydroelectric. Additional 

hydroelectric potential of more than 10 times the present 

production has been estimated. Geothermal potential 

has also been identified. Ground-water supplies are 

abundant and generally of excellent quality for most 

uses. 

Hydrologic problems in Costa Rica include flooding, droughts, surface- and ground-water contamination, 

waterlogged land, and overdevelopment of key aquifers. 

Costa Rica has developed some elements of the infrastructure necessary to resolve some of these problems. 

Some trained staff and laboratory facilities are 

available. Additional support is required to train scientists and technicians, acquire modern equipment and 

instrumentation, and develop selected areal and countrywide investigations. 

GEOLOGIC AND HYDROLOGIC HAZARDS 

Like its Central American neighbors, Costa Rica 

has a historical record of severe earthquakes. As recently 

as 1973, a large earthquake claimed 23lives. Earthquaketriggered failures of mountain slopes were the cause of all 

deaths and injuries. Landslides and debris flows gener0 

0 

EXPLANATION 

~Area of possible petroleum occurrence 

Reported occurrence of coal, by rank 

• Lignite 

A Subbituminous 

• Bituminous 

~ Geothermal site under exploration or 

development 

100 200 Kilometers 

50 100 Miles 

FIGURE 9. -Energy resource potential in Costa Rica. The seaward boundary is defined by the 200-m isobath. 

18 
CARIBBEAN 

SEA 

10°~--~--=---~~~~~~~~~~~~----~------10° 

86° 

0 

I 

0 

I 

50 

100 

I 

I 

200 Kilometers 

I 

100 Miles 

FIGURE 10. -Major surface-water features of Costa Rica. 

ated by earthquakes are a common hazard throughout 

Central America. 

Volcanic eruptions are also a major geologic hazard 

in Costa Rica. ArenaL a volcano in northwestern Costa 

Rica, erupted explosively in 1968, killing 78 people. 

Irazu, a volcano in the Central Cordillera of Costa Rica, 

erupted from 1963 to 1965, destroying several coffee 

plantations and covering San Jose and Carta go with ash. 

Geologic hazards may cause hydrologic hazards, as 

the eruption of the volcano Irazu did, when the ashfall 

polluted the water supplies of San Jose and other cities of 

the Meseta Central. 

GEOTHERMAL ENERGY 

Costa Rica's geothermal area extends for about 30 

km along the flank of the chain of young volcanoes. The 

geothermal development program in Costa Rica is 

focused on the geothermal field near Miravalles Volcano. 

An initial survey of about 2,000 km2 defined this area 

as the most promising in Costa Rica, and three deep 

exploration-production wells were drilted during 1979 

and 1980. On the basis of high reservoir temperatures 

(230° -245°C) and favorable flow test results, the Instituto Costarricense de Electricidad plans to begin development at this site by building a 25-MW geothermal 

plant. 

EL SALVADOR 

STATUS OF GEOLOGIC AND HYDROLOGIC 

INFORMATION AND PROGRAMS 

Geologic maps ofEl Salvador at various scales have 

been published principally by the Federal Republic of 

Germany (Bundesanstalt fur Geowissenschaften und 

Rohstoffe, 1976-1978; Weber and others, 1974). 

Volcanic mountain ranges containing active volcanoes extend over about 80 percent of the country. Sedimentary rocks, mostly sandstones and limestones, are 

intruded by igneous rocks. In addition, thick deposits of 

sedimentary rocks that were formed in ancient lakes are 

present in the Lempa Valley. The Government of El 

Salvador began a $1.5 million geological program in 

1981 to locate mineral deposits. Results of this study 

have not been published. 

19 
0 100 

0 50 

FIGURE 11.-Major geologic divisions and principal mineral 

deposits in El Salvador. Geology simplified from Case and Holcombe ( 1980). The metals contained in deposits are indicated by 

chemical symbols. Locality names are in parentheses. 

MINERAL RESOURCES AND POSSIBILITIES 

In 1981, El Salvador produced an estimated 1 ,000 

troy ounces of fine gold together with an estimated 

110,000 troy ounces of fine silver from its precious-metal 

mines (fig. 11 ). Gold production was down from a high 

of 3,619 troy ounces in 1978; silver was down from a 1978 

high of 185,000 troy ounces. Other mineral commodities 

produced were limestone and cement(table 1 ). Iron- and 

titanium-bearing sands are known to exist along the 

coast (Weyl, 1980). Silver, lead, and zinc deposits should 

be explored for along the concealed contacts of limestones and younger intrusive igneous rocks. The lake 

deposits should be examined for the possible presence of 

amber, which occurs in similar deposits in the Dominican 

Republic. 

ENERGY RESOURCES AND POSSIBILITIES 

No exploration for oil and gas in El Salvador has 

been reported, and no rights were held in 1982. The most 

recent known exploration, sponsored by the United 

Nat ions, consisted of seismic survey work over the 

Pacific shelf area (fig. 12) in 1974. The only area of the 

country that is at all prospective is that part of the narrow 

Pacific shelf shared with Nicaragua to the south. However, here the regional geologic conditions are not very 

favorable. 

El Salvador consists mostly of volcanic rocks that 

normally do not contain deposits of coal or hydrocarbons. Five lignite deposits are reported in intermontane 

20 

EXPLANATION 

Volcanic rocks 

200 Kilometers 

100Miles 

basins containing very young sediments containing 

organic matter. They warrant systematic evaluation 

(Bohnenberger and Dengo, 1978), particularly because 

they constitute a combustible fuel. 

WATER RESOURCES 

El Salvador has less abundant water resources than 

its neighboring countries. The varied physiography of 

the country results in a tropical climate; the average 

annual precipitation is about I ,830 mm (72 in.). Precipitation increases with elevation, from about 1,500 mm (59 

in.) at the coastal plains to as much as 2,300 mm (90 in.) 

in the mountain ranges. A bout 95 percent of the rainfall 

occurs from May to October; frequent severe droughts 

occur during the drier months. The main rivers in the 

country (fig. 13) include the Lempa and the San Miguel. 

Intermittent streams abound in the country. 

The principal hydrologic problems in El Salvador 

are related to overdevelopment of aquifers, droughts, 

surface- and ground-water contamination, and limited 

water-resources data. The geology of the country limits 

the extent and productivity of the aquifers (Seeger, 1962). 

Although ground water is generally of good quality, 

overdevelopment is already evident near San Salvador 

and in coastal areas. Unsewered facilities offer the potential for contamination of both ground- and surface-water 

supplies. 

Although water-resources data acquisition has improved recently, El Salvador needs technical, managerial, 

and financial support. 

GEOLOGIC AND HYDROLOGIC HAZARDS 

Severe earthquakes have had a major impact on El 

Salvador. Moderate-sized shallow earthquakes have 

destroyed or severely damaged San Salvador, the capital, 14 times. Because of their shallow origin, many 
0 50 

EXPLANATION 

- Area of possible petroleum occurrence 

• Reported occurrence of lignite coal 

• Operating geothermal powerplant 

~ Geothermal site under exploration 

or development 

200 Kilometers 

100 Miles 

FIGURE 12. -Energy resource potential in El Salvador. The seaward boundary is defined by the 200-m isobath. 

earthquakes have damaged a few closely spaced population centers but caused little damage to others nearby. 

Most of the earthquakes have occurred in the longitudinal depression that parallels the trend of volcanoes. A 

major seismic zone that has been seismically quiet for 

shallow events since 1950 has been identified along the 

coast of El Salvador. It has been suggested that this zone 

may be the site of a major earthquake in the near future. 

Volcanic eruptions are a continuing hazard for the 

citizens of El Salvador. New volcanoes such as lzalco 

have formed in historic time. San Salvador is located at 

the foot of Boqueron Volcano, which erupted with 

accompanying earthquakes in 1659 and 1917. Lake llopango on the eastern outskirts of San Salvador (fig. 13) 

occupies a huge volcanic depression (caldera). Landslides 

accompanying volcanic eruptions and earthquakes have 

caused additional problems for the capital city area. 

As in other countries of the region, the major hydrologic hazards are floods and drought. El Salvador tends. 

to be more prone to drought because it is located on the 

Pacific coast. It is rarely affected by hurricanes. 

Lago de Ouija 

go· 

14 •--l,oo=-~..o:::::=:,~~ ....... -7""'10.-t- Lago Coatepeque 

SAN 

go• 

100 200 Kilometers 

0 50 100Miles 

FIGURE 13 .-Major surface-water features of El Salvador. 

21 

GEOTHERMAL ENERGY 

El Salvador is the first Central American country to 

have constructed and operated geothermal electric powerplants. At the Ahuachapan field, three powerplants generate 95 MW and provide about 25 to 44 percent of the 

country's electricity from geothermal steam. Exploration 

began at Ahuachapan in the mid-1960's; by June 1975, 

the first single flash plant was in operation. The cost of 

three units at Ahuachapan was $96 million; however, 21 

days after the inauguration of the third unit in November 

1981, all three units had been paid for in oil savings. 

Berlin, another promising field about 90 km southeast of 

San Salvador (fig. 12}, is undergoing continued exploration by the Comision Ejecutiva Hidroelectrica del Rio 

Lempa. The capacity of the field has been estimated at 

110 MW and will probably be the site of El Salvador's 

fourth geothermal unit. 

GUATEMALA 

STATUS OF GEOLOGIC AND HYDROLOGIC 

INFORMATION AND PROGRAMS 

Detailed geologic mapping in Guatemala is incomplete (Weyl, 1980, p. 324-325). The only comprehensive 

geologic map of the country is at a scale of I: 50?,0~0 

(Bonis and others, 1970). Other geologic map senes m 

progress since 1966 include maps at scales of I :50,000, 

1:250,000 (I nstituto Geografico N acional de SJuatemal~, 

1965- 1975; Bundesanstalt fur Bodenforschung and I nstltuto Geografico N acional de Guatemala, 1967-1971; 

unpublished theses, State University of New York at 

Binghamton). 

The geologic terrane of Guatemala, unlike that of 

all other Central American countries except Belize, consists predominantly of sedimentary rocks; they cover 
about 60 percent of the country, mostly in the northern 

half, and extend into the Yucatan Peninsula of Mexico. 

An arcuate belt of young volcanic rocks covers about 20 

percent of the country near the Pacific Ocean. Intrusive, 

metamorphic, and volcanic rocks of the Guatemala 

Mass if form a mountainous highland north of the young 

volcanic rocks. Of special interest are ultramafic rocks 

that occur in the massif, occupy almost 5 percent of the 

country's area (fig. 14), and contain a world-class nickel 

deposit. Their location is controlled by the onshore 

extension of the Cayman trough (fig. 2). Guatemala is 

the only Central American country producing oil and 

gas. 

MINERAL RESOURCES AND POSSIBILITIES 

Guatemala produces or has produced antimony, 

chromite, copper, iron, lead, nickel, silver, tungsten, and 

zinc plus a wide variety of construction and industrial 

rocks and minerals. The world-class El Est or nickel mine 

(fig. 14), brought into production in 1977, was closed in 

1980 (Mining Journal, 1983) pending a return to more 

favorable world economic conditions. The Oxec copper 

mine (Petersen and Zantop, 1980) is of regional importance in size and production. Lead and zinc deposits are 

known to occur in the older metamorphic rocks, and 

other small high-grade deposits are likely to exist. Lead 

and zinc deposits similar to those in the limestones of the 

Mississippi Valley in the United States should be looked 

for in the limestones. Ultramafic rocks should be 

explored for chromium, platinum-group elements, and 

copper. Submarine volcanic rocks, such as those at the 

Oxec mine (Petersen and Zantop, 1980), appear to have 

formed at a spreading center (Kesler, 1978) and should 

also be examined for similar' deposits. 

90' 

ENERGY RESOURCES AND POSSIBILITIES 

The Rubelsanto and West Chinaja oilfields of Guatemala produced an average of6,600 bbl/ d of oil in 1981 

and thus provided the country a very important source of 

foreign exchange. These fields occur on the southern 

flank of the Chapayal-Peten Basin (fig. 15), a geologic 

extension of the same basin that contains the prolific 

Reforma oil district of Mexico. Results of 1981 exploration in Guatemala were highlighted by the discovery of 

oil (700 bbl/ d) at Well No. I Xan in the northwestern 

corner of the country. Exploration in this region will be 

continued by firms representing the United States and 

other countries. The changing character of producing 

formations southeast of the Mexican fields casts doubt 

on the possibility that fields of major size will be found in 

Guatemala, but additional small discoveries may be 

expected. 

Coal has been reported in II of Guatemala's 22 

departments; however, very little information on the 

character and extent of the coal beds is available. 

Records of analyses of a few coal samples are available, 

but a lack of information on sampling techniques used 

makes the analyses of questionable value. The general 

geology of Guatemala suggests that coal of three different geologic ages and three ranks (bituminous, su bbituminous, and lignite) may be present. Figure 15 shows 

the locations of reported occurrences. 

WATER RESOURCES 

Guatemala, the most populous country in Central 

America, has a varied climate dominated by the Sierra 

Madre mountain range. Precipitation in the highlands 

averages from 500 to 2,000 mm j yr (20- 79 in. j yr). In the 

EXPLANATION 

Sedimentary rocks 

and surficial cover 

~~l{;~:::i.:}~::j Intrusive rocks 

i":t,- :.-·:·--'J (mostly granites) 

W Volcanic rocks 

Ultramafic rocks 

Metamorphic rocks 

Pb,Zn JCaquipec and Suquinay mines) 

Cr (Cabanas and Jalapa d1strictsl 

Ag,Pb,Zn (San Pantale6n deposit( 

100 200Kilometers 

I 90 ' 

FIGURE 14. -Major geologic divisions and principal mineral deposits in Guatemala. Geology simplified from Case 

and Holcombe ( 1980). The metals contained in deposits are indicated by chemical symbols. Locality names are in 

parentheses. 

22 
100 200 Kilometers 

50 100 Miles 

lowlands of the Peten karst region, annual precipitation 

averages from 2,000 to 6,000 mm (79-236 in.). Toward 

the Pacific coastal region, equally intense rain produces 

annual averages ranging from 2,000 to 5,000 (79-199 in.). 

The principal rivers in Guatemala include the Motagua, 

Salinas, and Rio de Ia Pasion (fig. 16). The abundant 

rainfall and geomorphologic characteristics define 33 

distinct hydrologic basins. 

The main hydrologic problems in Guatemala include 

a complex combination of drought and floods, contamination of surface and ground water, overdevelopment of 

aquifers in the valley of the city of Guatemala, severe 

90 ' 

100 200K1Iomete1s 

50 100Miles 

FIGURE 16. -Major surface-water features of Guatemala. 

EXPLANATION 

- Area of possible petroleum occurrence 

23 

* 

• 

A 

• 

Site of petroleum development 

Reported occurrence of coal, by rank 

Lignite 

Subbituminous 

Bituminous 

Geothermal site under exploration or 

development 

FIGURE 15.-Energy resource potential in 

Guatemala. The seaward boundary is 

defined by the 220-m isobath. The 

location of the Chapayal-Peten Basin, 

which is a regional feature of interest in 

petroleum exploration, is shown. 

erosion and sedimentation in coastal areas, and limited 

informatio.n for the management of the water resources. 

The country has 400 MW of hydropower now in use and 

a large untapped hydroelectric potential of about 4,300 

MW. 

Droughts are frequent in the Pacific watershed, 

whereas occasional severe floods (two since 1969) affect 

large areas in the Peten region and the southeastern part 

of the country. Surface water is heavily contaminated 

with sewage discharge (only 28 percent of all households 

in the country have sewer connections), which also 

affects ground-water supplies near urban areas. In the 

valley of the city of Guatemala, ground-water overdevelopment is affecting optimal yields of well fields. 

Guatemala has prepared a master plan for the 

development of their water resources, and it has a limited 

number of trained professionals. The country needs 

additional financial and technical support to enhance its 

basic data-collection program. 

GEOLOGIC AND HYDROLOGIC HAZARDS 

Numerous historical accounts of damaging earthquakes in Guatemala date from the time of the Spanish 

conquest. Antigua, the original capital of Guatemala, 

was extensively damaged 10 times before a great earthquake in 1773 prompted the capital's relocation to the 

city of Guatemala. Before 1976, the city of Guatemala 

had experienced devastating earthquakes in 1917-18, 

1863, and 1862. In addition, great earthquakes having 

magnitudes of more than 8.0 on the Richter scale 

occurred less than I 00 km south of the city of Guatemala 

in 1902and 1942. ThegreatearthquakeofFebruary 1976 

occurred within the Motagua fault zone, the active 

boundary between the Caribbean and North America 

crustal plates (fig. 2). This earthquake claimed more than 
22,700 lives, injured more than 76,000 people, and produced losses totaling about $1.1 billion. 

Most of the 25 or so recently active Guatemalan 

volcanoes are clustered in three linear belts that parallel 

the Middle America thrust (fig. 2). Two of these volcanoes, Fuego and Santa Maria, have erupted in the last 4 

yr. The explosive nature of these eruptions makes them 

extremely hazardous. 

Flooding of the karstic depressions of northern 

Guatemala is a recurring serious problem for the city of 

Flores on Lake Peten Itza. 

GEOTHERMAL ENERGY 

At Zuni! in western Guatemala (fig. 15), a small 

high-temperature geothermal reservoir has been confirmed by drilling, and a I 5-MW geothermal unit is to be 

installed by I 986. In I 980, USGS scientists visited Guatemala to determine the geochemical character of the 

thermal waters at Zuni!. Another geothermal field , Amititlan, is also of interest. 

HONDURAS 

STATUS OF GEOLOGIC AND HYDROLOGIC 

INFORMATION AND PROGRAMS 

Geologic information necessary to evaluate the 

mineral resources of Honduras is inadequate. As of 

86° 

I 980, only 40 percent of the country had been topographically mapped at a scale of I :50,000. A geologic map 

of the entire country at l: 500,000 scale is available (Elvir 

A., 1974). 

In 1979, Honduras sought U.S. Reimbursable 

Development Program funding through the U.S. Embassy for feasibility studies on lignite and antimony mining projects. On June 2, I 980, the World Bank announced 

approval of a $3.65 million loan to provide technical 

assistance and training in petroleum exploration, pricing, 

and taxing . Honduras has also received assistance from 

the United Nations and Japan in projects involving gold 

occurrences in three specific areas (Vueltas de Rio, Zopotal, and Laguna Seca). The results have not yet been 

reported. 

The Government of Honduras is currently seeking a 

grant from the Inter-American Development Bank to 

fund technical assistance for a national mineral-resource 

inventory. USGS has provided a summary work plan for 

such a project at the request of the bank. 

The dominant geologic feature in Honduras is the 

Honduras Massif (fig. 17), a complex of metamorphic 

and igneous rocks occupying the northern part of the 

country. The massif covers about half the country and is 

geologically the oldest and tectonically the most stable 

terrane in Central America. Elsewhere, marine sedimentary rocks fill a central downfaulted block ,and flat-lying 

84° 

88° 

p 

CAKIBBEAN SEA 

Ag,Pb,Zn,Cd,Au 

(EI Mochito mine)~ 

./) 

fc; Golfo de 0~ ~ Fonseca 

"'1'4> 0 0 

0 

100 

50 

Ag,Pb,Zn (Las Animas deposit) 

200 Kilometers 

100Miles 

EXPLANATION 

r.TJGJ Sedimentary rocks' 

L:ii:iJ and surficial cover 

Volcanic rocks 

~~ Metamorphic rocks 

FIGURE 17. -Major geologic divisions and principal mineral deposits in Honduras. Geology simplified from Case and Holcombe ( 1980). 

The metals contained in deposits are indicated by chemical symbols. Locality names are in parentheses. 

24 
volcanic rocks of continental origin form a narrow plateau along the southern border, covering approximately 

20 percent of the country. 

MINERAL RESOURCES AND POSSIBILITIES 

The mineral industry, based on the production of 

gold, silver, zinc, lead, copper, cadmium, antimony, gypsum, and salt, contributed almost 3 percent of the country's gross domestic product in 1981, the largest proportion contributed by the mining industry of any Central 

American country. Most of the production was silver, 

lead, and zinc from the El Mochito mine (fig. 17), the 

largest working mine in Central America in terms of 

total mining production and diversity of mineral products. Two additional deposits of regional importance 

containing silver, lead, and zinc ores are El Rosario and 

Las Animas (Guild, 1981, p. A39). Honduras led all 

Central American countries in silver production, producing 2,400,000 troy ounces in 1981 (Ensminger, 1983). 

Antimony, copper, and mercury have been mined in 

the past (Roberts and Irving, 1957, p. 205}, and manganese and iron deposits are known (Klemic, 1970; National 

Materials Advisory Board, 1981), but none of these are 

reported to be mined at present. Shale and sandstone 

northeast of Tegucigalpa accumulated in a geologic setting that may be similar to the setting of some N orilsk 

copper- and nickel-bearing deposits in other parts of the 

world. These rocks should be examined futher to determine the likelihood of copper and nickel deposits 

occurring. 

86° 

./) 

~0 Golfo OD.L-. ~ Fonseca 

ENERGY RESOURCES AND POSSIBILITIES 

Oil and gas have been sought in Honduras, both 

onshore and offshore, not only on the coastal plain and 

in the Caribbean (fig. 18) but also in small intermontane 

basins. Thusfar, no discoveries have been made, but oil 

seeps have been reported. The most favorable area is 

offshore in the Caribbean, where thick layers of carbonate and clastic rocks are present on the Nicaragua Rise. 

Drilling, to depths of 3,000 to 4,500 m ( l 0,000-15,000 ft}, 

has not revealed the presence of source rocks or of 

temperatures that would lead to hydrocarbon development. Nevertheless, interest is still being shown by companies, including one U.S. firm holding exploration 

permits. 

Coal has been reported at 10 different localities in 

Honduras (fig. 18). Of these, six are in relatively old 

rocks. One of these coals may be of bituminous rank, 

and four are probably of subbituminous rank. Four that 

are in relatively young rocks are lignite. Some data available on the older coals indicate that beds more than I m 

(3.3 ft) thick are present in several localities; one bed 

ranging in thickness from 2 to 5 m (6.4-16 ft) has been 

reported. Most of these coal beds have high ash content 

but low to medium sulfur content. From the brief descriptions, it appears that much of the ash may be in 

interbeds or partings of shale within the beds of the coal 

sequence. This deleterious material can be removed readily by gravity separation. 

Lignite is reported at four localities, but information 

on the beds is available for only one of them. The lignite 

there is 1.8 m (5.7 ft) thick but has a high ash content. 

84" 

EXPLANATION 

~ Area of possible petroleum occurrence 

Reported occurrence of coal, by rank 

• Lignite "<;"~0 0 

1

1----.--1-1 --r--'1fc___----,...--'2jl0 Kilometers .A I I I 

Subbituminous 

0 50 100Miles Bituminous? • FIGURE 18.-Energy resource potential in Honduras. The seaward boundary is defined by the 200-m isobath. 

The location of the Nicaragua Rise, which is a regional geologic feature of interest in petroleum exploration, is shown. 

25 
WATER RESOURCES 

Honduras, the second largest country in Central 

America, has a rugged topography (80 percent mountains) and a moderate temperate climate. Annual average precipitation ranges from 1,500 mm (60 in.) in the 

interior valley to as much as 3,000 mm ( 118 in.) in the 

north-central mountains. Most of the rain occurs from 

April to October and results in frequent floods and 

droughts. The country is also affected by frequent hurricanes from the Caribbean (five since 1965). The principal 

rivers in the country include the Patuca and the Ulua 

(flowing to the Caribbean) and the Choluteca (flowing to 

the Pacific) (fig. 19). 

Hydroelectric generation provides about 61 percent 

of the power used in Honduras, but the country's potential (about 4,000 MW) is largely untapped. Geothermal 

energy potential has also been identified in Honduras. 

The ground-water resources of Honduras are limited 

by the low porosity and permeability of the aquifers 

formed by volcanic rocks. The most productive aquifers 

occur in the alluvial valleys of the Choluteca and Guayape 

Rivers, where yields from wells can be as high as 60 LIs 

(900 gal/ min). Ground-water development is significant 

along the northern area for banana plantations and in 

the Tegucigalpa area for the water supply. 

The principal hydrologic problems in Honduras are 

frequent floods and droughts, contamination of surface 

and ground water, and limited information for the 

development and management of water resources. A 

National Ground Water Service was recently funded to 

prepare a national ground-water development program. 

Technical support is needed to provide additional 

training, and financial support to acquire equipment and 

facilities is essential. 

GEOLOGIC AND HYDROLOGIC HAZARDS 

The threat of damaging earthquakes and volcanic 

eruptions is not as great in Honduras as it is in most other 

Central American countries. Earthquakes do, however, 

occur and tend to be concentrated along the northern 

seacoast. Caribbean hurricanes have caused severe flooding in Honduras. Hurricane Fifi caused major damage 

and loss of life in 1974. The southern and western portions of the country are subject to drought whenever 

there is a delay in the onset of the rainy season. 

GEOTHERMAL ENERGY 

In 1977, a geothermal exploration program, now in 

abeyance, was focused on the Pavana area near Choluteca 

86° 

p 

CARIBBEAN SEA 

FIGURE 19. -Major surface-water features of Honduras. 

26 
ing in the southernmost part of the country and on the 

San Ignacio area northwest of Tegucigalpa. 

NICARAGUA 

STATUS OF GEOLOGIC AND HYDROLOGIC 

INFORMATON AND PROGRAMS 

A preliminary geologic map of Nicaragua at a scale 

of I: 1,000,000 (Martinez and Kuang, 1973) has been 

published in addition to other geologic maps at scales of 

I :250.000 (Weyl, 1980, p. 327). 

More than half the country is covered by young 

flat-lying volcanic rocks that overlie the older metamorphic and crystalline basement rocks exposed in the 

northern part ofNicaragua(fig. 20) and in the Honduras 

Massif. A chain of volcanoes, many of which have been 

active in historic time, parallels the Pacific coast in the 

southwestern part of the country. The Caribbean coastal 

plain is made up of a thick sequence of sedimentary 

rocks consisting of sandstone, shale, and limestone of 

both continental and marine origin. 

MINERAL RESOURCES AND POSSIBILITIES 

Minerals produced in Nicaragua in 1981 included 

gold, silver, and the industrial rocks and materials (gypsum, anhydrite, salt, sand, lime, and cement). Nicaragua's output of 70,000 troy ounces of gold in I981 was 

the largest of any Central American country (table I). 

World-class mines producing gold are Sententrion (formerly El Limon), Siuna, and Vesubio (fig. 20. table 2). 

Small amounts of copper, lead. and zinc were produced 

prior to I972. Occurrences of antimony, tungsten, 

molybdenum, and phosphate have also been reported 

(Levy, 1970; Cathcart, 1977; Weyl, 1980). 

ENERGY RESOURCES AND POSSIBILITIES 

Exploration for oil and gas has been conducted in 

both the Caribbean and the Pacific areas of Nicaragua; 

although a deep test drilled offshore in the Caribbean by 

the Shell Oil Company was reported to have found oil at 

about 3,600 m ( I1,800 ft), offsetting holes have not been 

productive. The best aspects for oil and gas are in the 

thick carbonate and clastic rocks of the Nicaragua Rise 

(fig. 21 ) . Several tests drilled in the narrow basin along 

the Pacific coast have been unsuccessful. 

Exploration has been halted by the unsettled political situation in Nicaragua. No activity has been reported 

since I980, although 52,633 km2 in concessions were still 

held at the end of 1981. 

Cu,Au,Ag (Siuna mine) 84" 

Au,Ag,Pb,Zn (Vesubio mine) 

£) 

CARIBBEAN 

SEA 

EXPLANATION 

86" 84" 

0 100 200 Kilometers 

~Metamorphic rocks 

0 50 100 Miles 

FIGURE 20.-Major geologic divisions and principal mineral deposits in Nicaragua. 

Geology simplified from Case and Holcombe (1980). The metals contained in 

deposits are indicated by chemical symbols. Locality names are in parentheses. 

27 
N 

00 

0 100 200 Kilometers 

0 50 100 Miles 

EXPLANATION 

-Area of possible petroleum 

occurrence 

• Reported occurrence of lignite coal 

+ Operating geothermal powerplant 

FIGURE 21. -Energy resource potential inN icaragua. The seaward boundary is defined by the 200-m isobath. The location of the Nicaragua 

Rise, which is a regional geologic feature of interest in petroleum exploration, is shown. 
Nicaragua is said to have lignite in seven localities 

(fig. 21), but no data on the occurrences have been 

reported. 

WATER RESOURCES 

Nicaragua, the largest country in Central America, 

has abundant surface- and ground-water resources. Precipitation ranges from as little as 400 mm/yr (16 in.jyr) 

in the western highlands to as much as 6,300 mm/ yr (250 

in./yr) in the wet, humid Caribbean plain. In most of the 

country, rainfall ranges from 2,400 to 4,000 mm/yr 

(95-157 in./ yr). The principal rivers inN icaragua include 

the Rio Grande de Matagalpa, the Coco, the Prinzapolka, and the San Juan, all flowing to the Caribbean 

(fig. 22); all are partially navigable. Nearly 90 percent of 

the runoff is to the Caribbean. Floods are not frequent in 

Nicaragua, but the Caribbean coast is vulnerable to 

hurricanes. Hydroelectric and geothermal energy production is significant, and there is additional undeveloped 

potential. Nicaragua also has ample water supplies from 

Lakes Managua and Nicaragua. 

Ground water meets most of Nicaragua's industrial 

and domestic needs. Water use in 1972 was about 40 

million cubic meters, 75 percent of which was for industrial use. Projected use for 1982 was about 90 million 

cubic meters. Overdevelopment ofthe country's aquifers 

is occurring in the major metropolitan areas of ManaguaGranada, Leon, and Chinandega. Seawater intrusion 

has been detected in areas along the Pacific shore. Contamination of surface- and ground-water supplies by 

sewage discharge has been identified as one of the most 

significant water-resources problems (only about 40 percent of all households have sewer connections). 

A significant data base of the ground-water resources of the country has been developed and detailed investigations made in several areas. Technical support is 

needed to train additional staff in modern techniques 

and procedures for water-resources data collection, 

appraisal, and management. 

GEOLOGIC AND HYDROLOGIC HAZARDS 

Earthquakes are frequent inN icaragua. Most originate along the Middle America thrust (fig. 2), which 

results from the northeasterly movement of the Cocos 

plate beneath the Caribbean plate. Epicenters of earthquakes are often located at the intersections of the topographic depression that parallels the trend of Central 

American volcanoes and the depressions that run transverse to the coastline. Such is the case at Managua, 

capital city of Nicaragua, which has been repeatedly 

29 

destroyed by earthquakes. Most recently, in December 

1972, a severe magnitude 6.2 earthquake killed over 

11 ,000 people, caused more than half a billion dollars in 

property damage, and destroyed 75 percent of Managua's 

housing. A long-time seismically quiet zone has recently 

been identified off the Pacific coast of Nicaragua, 

southwest of Managua. It has been postulated that an 

earthquake of magnitude greater than 7 .will occur in this 

area in the next several decades. 

In addition to geologic hazards related to earthquakes, Nicaragua has had a long history of active volcanism. At least eight volcanoes have erupted in the last 

century. Two of the three most explosive and potentially 

devastating volcanoes in Nicaragua (Apoyeque and 

Apoyo) are within 35 km of the center of Managua. 

Clearly, volcanic risk needs to be carefully evaluated and 

taken into account in urban planning for Managua. 

Although earthquakes and volcanoes are the most 

prominent natural hazards, Nicaragua is also prone to 

drought and occasionally to flash flooding. The Caribbean coast is subject to hurricanes, and the Pacific coast 

often suffers drought during the dry season. 

GEOTHERMAL ENERGY 

This year, Nicaragua joined El Salvador as a geothermal energy producer. A 35-MW plant, which began 

operation in August near M omotombo Volcano, provides 12 percent of Nicaragua's energy needs (fig. 21). 

Italy is the primary financial backer of this project. 

PANAMA 

STATUS OF GEOLOGIC AND HYDROLOGIC 

INFORMATION AND PROGRAMS 

Semi detailed geologic mapping has been carried out 

in parts of Panama as part of the United Nations Development Program (Administracion de Recursos Minerales, 1969-1971 ), in the Panama Canal Zone and vicinity by the USGS (Stewart and Woodring, 1980), and for 

the entire country (Larocque and others, 1972; Direccion 

General de Recursos Minerales, 1976). Modern detailed 

geologic maps needed to identify and assess resources are 

virtually nonexistent, and the geologic map of Panama 

(fig. 23) is highly generalized. 

Nearly 70 percent of the country consists of volcanic 

rocks. The arcuate belt of folded volcanic rocks in the 

east is submarine in origin. Volcanic rocks of continental 

origin along with intrusive rocks occupy a broad platform in the western part of Panama. A thick section of 

marine sedimentary rocks that may be favorable for 
w 

0 

£) 

·r~ / _( / '=h cf&/ 14o 

CARIBBEAN 

SEA 

17 

120 ,..0 \ u _____ p If . ........,\ ..... , ,.. l, d'dl 12° 

"7. 

~ y. 

86° 84° 

0 100 200 Kilometers 

0 50 100 Miles 

FIGURE 22. -Major surface-water features of Nicaragua. 
78° 

o··-----+--- ------+---------~ lo · 

82. so· 

CARIBBEAN SEA 

Cu,Mo 

(Cerro Colorado deposit) 

82. PACIFIC 

100 200 Kilometers 

50 100 Miles 

Mn (Nombre de Dios- i6 Boquer6n area) 

,- -~.,Mn (Mandin a area) 

so· OCEAN 78. 

EXPLANATION 

- Ultramafic rocks 

FIGURE 23 . -Major geologic divisions and principal mineral deposits in Panama. Geology simplified from Case and Holcombe (1980). The 

metals contained in deposits are indicated by chemical symbols. Locality names are in parentheses. 

hydrocarbons is present at the eastern half of the isthmus. Small areas of ultramafic rocks are present on the 

peninsula southwest of the city of Panama (Case and 

Holcombe, 1980). 

MINERAL RESOURCES AND POSSIBILITIES 

Mineral-industry production in 1981 was confined 

almost entirely to limestone and clay (Ensminger, 1983). 

The country has extensive resources of copper and 

molybdenum at two deposits (Cerro Colorado and 

Petaquilla) (fig. 23) (Prokop, 1975, p. 42), but low world 

copper prir:es and the high cost of energy have inhibited 

development of these resources (Mining Journal, 1983). 

Aluminum resources are reported in the provinces of 

Chiriqui and Veragas (Patterson, 1967, p. 40). Alluvial 

gold has been produced in the past and, together with 

titanium, platinum, and rare-earth-bearing sands, might 

well be explored for in nearshore submerged deposits. 

Gold has been produced in many places in the past; 

before the mid-19th century, the El Espirito Santo mine 

was one of the largest gold producers in the western 

hemisphere. Rocks and a geologic setting similar to those 

that host the Pueblo Viejo mine in the Dominican 

Republic (one of the largest gold mines in the western 

hemisphere) (Kesler, 1978) are reported to exist here 

(Stewart, 1975) and should be examined for the presence 

of disseminated gold deposits. Manganese has been produced in the past, and areas of submarine volcanic rocks 

31 

that may have the same type of geologic setting that hosts 

the large manganese deposits of Cuba should be examined for additional deposits. Phosphate has been reported · 

(Cathcart, 1977). Additional copper and molybdenum 

deposits could probably be located by using new exploration techniques. 

ENERGY RESOURCES AND POSSIBILITIES 

Oil and gas possibilities in Panama are limited 

because of the predominance of volcanic rocks, which 

generally do not include good source or reservoir rocks. 

Reef limestones may offer prospective targets, and the 

relatively high heat flow on the Pacific side of the isthmus 

favors the formation of petroleum at reasonable drilling 

depths. Considerable drilling done in intermontane basins in southeastern Panama suggests that shows of oil 

may have been encountered. The offshore continental 

shelf is narrow (fig. 24) on the Caribbean coast but rather 

broad on the Pacific side. Recent petroleum leasing in 

the Gulf of Chiriqui and the Gulf of Panama indicates 

that industry is interested in that area. 

Coal beds were reported in northwestern Panama 

more than a century ago by Evans (1861). He regarded 

the coal beds as geologically and geographically favorable for development. These beds crop out on the mainland and islands surrounding Laguna de Chiriqui, which 

forms the largest and safest harbor on the Caribbean 

coast of Central America. Evans measured coal beds 
50 

EXPLANATION 100 200K1Ion1eters B Area of possible petroleum occurrence 

100M lies 

Reported occurrence of coal, by rank 

• Lignite 

& Subbituminous 

~ Geoth ermal site under exploration 

or development 

FIGURE 24. -Energy resource potential in Panama. The seaward 

boundary is defined by the 200-m isobath. 

from 0.6 m (2 ft) to as much as 1.7 m (6 ft) thick at a 

number of localities. He reported that the coal was low in 

ash and sulfur, but the sampling and analytical procedures on which his determination was based are not 

known. The coal may be of sub bituminous rank, similar 

to the coal across the western border in Costa Rica. No 

systematic mapping, exploration, or appraisal of these 

coal beds has been undertaken. 

The coal in the Laguna de Chiriqui area might be a 

significant resource and should be explored. A proposal 

for investigating this coal is under consideration by 

USAID. Lignite has been reported at nine localities in 

Panama (fig. 24), but information on thickness and quality of the beds is lacking. 

WATER RESOURCES 

Panama has a tropical humid climate; annual precipitation ranges from 1,500 to 5,500 mm (59-198in.). 

Two distinct physiographic zones occur: the Caribbean 

watershed, which is affected by trade winds and tropical 

disturbances, and the Pacific shores, which include the 

Azuero Peninsula (to the south) and the Darien area (to 

the southeast). Precipitation varies throughout the year 

and affects runoff significantly. Extreme droughts are 

not frequent but can occur in the Azuero area. The 

principal rivers in the Caribbean watershed (30 percent 

32 

of the country area) include the Changuinola and the 

Code del N orte(fig. 25). In the Pacific area, the Chiriqui, 

the Santa Maria, and the Chepo are the main rivers. 

Surface water provides most of Panama's urban 

water needs. Flooding occurs frequently in response to 

tropical disturbances and to hurricanes in the Caribbean 

area. 

Ground-water development in Panama has been 

limited to small wells for rural areas and industrial facilities. A generalized assessment of the ground-water 

resources of the country is not available. Preliminary 

investigations indicate that aquifers can yield as much as 

500 gal/ min in selected areas. 

The principal hydrologic problems in Panama 

include lack of water-resources information, contamination of surface and ground water, and erosion and sedimentation. The lack of sewer facilities in about 30 percent of all households contributes to contamination of 

surface and ground water. 

Technical and financial assistance is needed in the 

form of training personnel, acquiring equipment, and 

supporting facilities. 

GEOLOGIC AND HYDROLOGIC HAZARDS 

The junction of several major crustal plates is 

located in Panama. Because earthquakes commonly 

occur where plates collide or slide past one another, 

Panama has experienced numerous damaging earthquakes. Earthquake hazards are a major concern not 

only to Panama but also to the United States because 

they threaten power facilities in the Canal Zone and the 

integrity and stability of the canal itself. Large earthquakes have the potential to trigger massive landslides 

along the canal banks (many of which are composed of 

weak clay) and to damage lock and dam facilities. 

The major hydrologic hazards in Panama are flash 

floods that affect flood-plain communities. 

GEOTHERMAL ENERGY 

Geothermal resources are believed to exist in Panama, where extensive volcanic deposits and high heat flow 

create favorable conditions. Preliminary feasibility studies, like those done at Baru-Cerro Colorado (fig. 24), 

are supported by the Inter-American Development Bank 

and are currently in progress. 

CONCLUSIONS AND RECOMMENDATIONS 

Effective long-range economic growth and development in Central America needs to include development 

of indigenous mineral, energy, and water resources for 
82° 80° 78° 

10°------------+----------------------+----------------------~rloo 

CARIBBEAN SEA 

PACIFIC 80° OCEAN 

0 

I 

0 

I 

50 

100 

I 

200 Kilometers 

I 

I 

100Miles 

FIGURE 25 .. -Major surface-water features of Panama. 

domestic, agricultural, industrial, and trade purposes. 

The results of this review indicate that (I) excellent conditions exist for discovery and development of additional 

mineral and energy resources, (2) there is a history of 

natural disasters and a continuing threat from geologic 

and hydrologic hazards, and (3) substantial benefits will 

result from a rational development of water resources. 

Scientific and technical assistance to Central American countries is essential for the development of their 

natural resources. The elements of such assistance 

should include (1) preparation of a systematic, detailed analysis of the status of geologic and hydrologic 

information, (2) a cooperative review of the need for 

additional earth-science activities, and (3) the definition of specific activities needed for mineral-, 

energy-, and water-resources evaluation and geologic 

and hydrologic hazard mitigation. All activities 

should be designed to train national scientists and to 

strengthen local institutions. 

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Bohnenberger, O.H., and Dengo, G., 1978, Coal resources in Central 

America, in Coal resources of the Americas: Geological Society of 

America Special Paper 179, p. 65-72. 

Bonis, Samuel, Bohnenberger, O.H., and Dengo, Gabriel, 1970, 

Mapa geologico de Ia Republica de Guatemala: Guatemala Instituto Geografico Nacional, scale I :500,000. 

33 

Bulkley, J .W., McLaughlin, R.T., and Ibanez, F., 1965, On the water 

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Guatemala, 1967-1971, Mapa geologico general (de Ia Republica 

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Hannover, scale 1: 100,000. 

Case, J.E., and Holcombe, T.L., 1980, Geologic-tectonic map of the 

Caribbean region: U.S. Geological Survey Miscellaneous Investigations Map 1-1100, scale I :2,500,000. 

Cathcart, J':R, 1977. Distribution and resources of phosphate in the 

eastern United States and Latin America, in Raup, O.B., ed., 

Proceedings of the Geology and Food Conference, with related 

U.S. Geological Survey projects and a bibliography: U.S. Geological Survey Circular 768, p. 3-7. 

Deal, C.S., 1982, Oil and gas developments in South America, Central 

America, Caribbean area. and Mexico in 1982: American Association of Petroleum Geologists Bulletin, v. 67. no. 10, p. 1849-1883. 

Direccion General de Recursos Minerales, 1976, Mapa geologico, 

Republica de Panama: Panama Ministerio de Comercio e Industrias. scale I : I ,000,000. 

Dondoli, Cesar, Dengo, Gabriel, and Malavassi, Enrique, and others, 

1968, Mapa geologico de Costa Rica. edicion preliminar: Costa 

Rica Direccion de Geologia. Minas y Petroleo, Ministerio de 

Industria y Comercio, scale I :700,000. 

Drummond, K.J., Moore, G.W., Golovchenko, X., Larson, R.L., 

Pitman, W.C., III, Reinhart, W.A., Simkin, T., and Siebert, L., 

1981. Plate-tectonic map of the circum-Pacific region, northeast 

quadrant: Tulsa, American Association of Petroleum Geologists, 

scale I : I 0,000,000. 

Drummond, K.J., Corvalan, J., Moore, G.W., McCoy, F.W., Swint, 

T.R., and Richards, P.W., 1983, Geologic map of the circumPacific region, northeast quadrant: Tulsa, American Association 

of Petroleum Geologists, scale 1: I ,000,000. 
ElvirA., Reniery, 1974, Mapa geologico de la Republica de Honduras: 

Honduras Instituto Geografico Nacional, scale 1:500,000. 

Ensminger, H.R., 1983, The mineral industry of~entral American 

countries, in U.S. Bureau of Mines, 1981 minerals yearbook, v. 

III, Area reports, international: Washington, D.C., U.S. 

Government Printing Office, p. 1267-1287. 

Erickson, R.L., compiler, 1982, Characteristics of mineral deposit 

occurrences: U.S. Geological Survey Open-File Report 82-795, 

227 p. 

Evans, J ., 1861, Geological report, in Reports from the Chiriqui Commission: Message from the President of the United States, House 

of Representatives, Executive Document No. 41. 

Gawarecki, S.J., Moxham, R.M., Morgan, J.O., and Parker, D.C., 

1980, An infrared survey of Irazu and vicinity, Costa Rica, in 

International Symposium on Remote Sensing of Environment, 

14th, San Jose, Costa Rica, Aprill980, Proceedings: Ann Arbor, 

Environmental Research Institute of Michigan, p. 1901-1912. 

Grunwald, J., and Musgrove, P., 1970, Natural resources in Latin 

American development: Baltimore, Johns Hopkins Press, 494 p. 

Guild, P. W., 1981 a, Preliminary metallogenic map ofN orth America: A 

numerical listing of deposits: U.S. Geological Survey Circular 

858-A, 93 p. 

___ 1981 b, Preliminary metallogenic map of North America: An 

alphabetical listing of deposits: U.S. Geological Survey Circular 

858-B, p. B I-B72. 

Instituto Geografico Nacional, 1965-1969, Geologia del area, Republica de Guatemala: Guatemala City, scale 1:250,000. 

___ 1966-1975, Mapa geologico de Guatemala: Guatemala City, 

scale I: 50,000. 

___ 1967, Mapa de Reconociemento geologico de Ia region de Ia 

Republica de Guatemala: Guatemala City, scale I: 125,000. 

Kesler, S.E., 1978, Metallogenesis of the Caribbean region: Geological 

Society of London, v. 135, pt. 4, p. 429-441. 

Klemic, H., 1970, Iron ore deposits of the United States of America, 

Puerto Rico, Mexico, and Central America, in Survey of world 

iron ore resources: New York, United Nations, p. 411-477. 

Larocque, J., Metti, A., Recchi, G., Roquebert, J., Stewart R., del 

Giudice, D., Esquivel, D., Lovell, J., Luque, V., Merida, A., and 

Torre, F., 1972, Mapa geologico preliminar, Republica de 

Panama: Panama Direccion General de Recursos Minerales, 

Ministerio de Comercio e Industrias Open-File Map, scale 

I: I ,000,000. 

Levy, E., 1970, Estudios metalogeneticos de America Central: Guatemala Institutio Centroamericano de Investigacion y Tecnologia 

Industrial, 57 p. 

Martinez H., M.A., and KuangS.,Juan, 1973, Mapa geologico preliminar, Republica de Nicaragua: Nicaragua Instituto Geografico 

N acional, scale I: I ,000,000. 

Martino, 0., Hyde, D., and Velasco, D., 1981, Mineral industries of 

Latin America: U.S. Bureau ofMines Mineral Perspectives, 116 p. 

Mining Journal, 1983, Mining annual review-Centml and South 

America: London, p. 325-328. 

Mining Magazine, 1983, Mining activity in the western world: v. 145, 

no. I, p. 40--68. 

National Materials Advisory Board, 1981, Manganese reserves and 

resources of the world and their industrial implications: Washington, D.C., National Academy of Sciences, 334 p. 

North American Metallogenic Map Committee, 1981, Metallogenic 

map of North America: Reston, Va., U.S. Geological Survey, 

scale I :500,000,000. 

Patchick, P.F., 1968, Ground-water research in Central America completed: Water Well Journal, v. 22, no. 10, p. 32-33. 

34 

Patterson, S.H., 1967, Bauxite reserves and potential aluminum resources of the world: U.S. Geological Survey Bulletin 1228, 176 p. 

Petersen, E. U ., and Zantop, Half, 1980, The Oxec deposit, Guatemala: 

An ophiolite copper occurrence: Economic Geology, v. 75, no. 7, 

p. 1053-1065. 

Prokop, F.W., 1975, The future economic significance of large lowgrade copper and nickel deposits: Berlin, Gebruder Borntraeger, 

Monograph Series on Mineral Deposits, no. 13, 67 p. 

Roberts, R.J., 1944, Manganese deposits in Costa Rica: U.S. Geological Survey Bulletin 935-H, p. H387-H414. 

Roberts, R.J., and Irving, E.M., 1957, Mineral deposits of Central 

America: U.S. Geological Survey Bulletin 1034, 205 p. 

Salas, G.P., 1982, Preliminary study of mineral resources of Latin 

America, in Whitmore, F.C., Jr., and Williams, M.E., eds., 

Resources for the twenty-first century: U.S. Geological Survey 

Professional Paper 1193, p. 183-191. 

Seeger, D., 1966, Regional hydrogeology of El Salvador, in 3d 

Caribbean Geological Conference, Kingston, Jamaica, April 

1962: Geological Survey of Jamaica Publication 95, p. 95-97. 

Skinner, B.J., ed., 1981, Economic Geology, Seventy-fifth anniversary 

volume: Blacksburg, Va., Economic Geology Publishing Company, 964 p. 

Stewart, R.H., 1975, Panama, in Fairbridge, R.W., ed., The encyclopedia of world regional geology, pt. I: Stroudsburg, Pa., 

Dowden, Hutchison, and Ross, p. 416-418. 

Stewart, R.H., and Woodring, W.P., 1980, Geologic map of the 

Panama Canal and vicinity, Republic of Panama: U.S. Geological 

Survey Miscellaneous Investigations Map I-1232, scale I: 100,000. 

United Nations, 1976, Ground water in the Western Hemisphere: 

Natural Resources/Water Series, no. 4, 336 p. 

___ 1980, Replies to questionnaire on' 'Status of Water Resources 

Development-Progress and Perspectives since the UN Water 

Conference" from El Salvador, Nicaragua, Costa Rica, and 

Panama: New York. 

United Nat ions Development Program, 1981, Latin America regional 

program priorities paper 1982-1986, UNDP 1 ECLA special meeting, May 13, 1981, Montevideo, Uruguay, Document 3. 

United Nations Educational, Scientific, and Cultural Organization, 

1982, Experts meeting on the major regional project on the utilization and conservation of water resources in the rural areas of Latin 

America and the Caribbean, final report: Paris, 33 p. 

U.S. Army Corps of Engineers, 1965, Costa Rica-Regional analysis 

of physical resources, Central America and Panama: Washington, 

D.C., USAID Resources Inventory Center, 33 p. 

U.S. Agency for International Development, 1982, Country profiles: 

Washington, D.C., Office of Foreign Disaster Assistance. 

Weber, H.S., Wiesemann, G., and Wittekindt, H., 1974, Mapa 

geologico general de Ia Republica de El Salvador: Hannover, 

Bundesanstalt fur Bodenforschung, scale I :500,000. 

Weyl, Richard, 1980, Geology of Central America, 2d ed.: Berlin, 

Gebruder Borntraeger, 371 p. 

Winch, K.L., ed., 1976, International maps and atlases in print, 2d ed.: 

London, Bowker, 666 p. 

Woakes, M., and Carman, J.S., eds., 1983, AGIO guide to mineral 

resources development: Bangkok, Association of Geoscientists 

for International Development Report Series no. 10, 504 p. 

Woodring, W.P., 1957, Geology and paleontology of Canal Zone and 

adjoining parts of Panama: Geology and description of Tertiary 

mollusks (Gastropods: Trochidae to Turritellidae): U.S. Geological Survey Professional Paper 306-A. 145 p., 23 pis., 4 figs. 

Woodring, W.P., and Thompson, T.F., 1949, Tertiary formations of 

Panama Canal Zone adjoining parts of Panama: American Association of Petroleum Geologists Bulletin, v. 33, no. 2, p. 223-247. 
APPENDIX 1.-U.S. GEOLOGICAL SURVEY ACTIVITIES IN CENTRAL AMERICA AND 

BIBLIOGRAPHY OF REPORTS RESULTING FROM U.S. GEOLOGICAL SURVEY SCIENTIFIC 

AND TECHNICAL COOPERATION WITH CENTRAL AMERICAN COUNTRIES, 1940-1983 

The U.S. Geological Survey has had active scientific 

programs in many Caribbean Basin and South American countries. USGS has provided technical assistance 

and (or) training in resource investigation and hazard 

mitigation, with excellent results, to Argentina, Bolivia, 

Brazil, Chile, Colombia, Costa Rica, Cuba, Ecuador, El 

Salvador, Guatemala, Guyana, Haiti, Nicaragua, Panama, Paraguay, Peru, Santo Domingo, St. Vincent, and 

Venezuela. 

Initial studies in Central America include a summary 

report on strategic and other significant minerals in Central America (Roberts and Irving, 1942) done under the 

auspices of the Interdepartmental Committee on Scientific and Cultural Cooperation (ICSCC) of the Department of State. Roberts also investigated the manganese 

deposits in Costa Rica (Roberts, 1944) and manganese 

and antimony deposits in Honduras. From 1943 to May 

1945, several USGS geologists investigated mineral deposits in Guatemala, Honduras, El Salvador, Nicaragua, 

and Panama (Roberts and Irving, 1957). Water resources 

studies were made in El Salvador from 1943 to 1944, in 

Nicaragua in 1943 and 1949, in Panama in 1949, and 

again in El Salvador in 1947. The reports describing 

these studies are listed in this appendix. 

The only USGS study directly related to petroleum 

exploration in Central America was made in 1946 by 

W.P. Woodring, who collected and described fossils in 

Tertiary formations in Panama to determine their possible use as a tool in the search for petroleum. The project 

was sponsored by the ICSCC in cooperation with the 

Government of Panama (Woodring, 1957; Woodring 

and Thompson, 1949). 

A 5-week study of Guatemalan mineral resources 

was made by R.L. Miller in 1961 at the request of the 

Government of Guatemala and sponsored by the International Cooperation Agency. Miller advised the Direccion de Minas y Hidrocarburos and the Direccion General de Cartografia on the potential for industrial 

minerals and coal in an effort to widen Guatemala's 

economic base. 

In J 9_63, Irazu Volcano began a catastrophic eruption that dumped ash on the surrounding countryside 

over a 2-yr period. The resulting crop damage, landslides, 

mudflows, and accelerated erosion caused widespread 

35 

economic hardship. Early in 1964, the USGS conducted 

an aerial infrared heat sensing survey of the volcano, 

sponsored by US AID in cooperation with the University 

of Michigan and the Costa Rican Instituto Geografico 

(Gawarecki and others, 1980). Later that same year, 

USGS began a project to help the Government of Costa 

Rica mitigate the effects of future eruptions. The work, 

done in cooperation with the Direccion de Geologia, 

Minas y Petroleo, included installation of permanent 

seismographs to monitor volcanic activity, water-supply 

study, and geologic mapping. Detailed slope-stability 

maps and reports and geologic maps were prepared. 

Recommendations for protection from future mud and 

debris flows and floods and the training of counterpart 

scientists ensued. 

- In the 1960's, Miller was instrumental in initiating 

and stimulating the development of a School of Central 

American Geology at the University of Costa Rica to fill 

an almost complete void of native-born geologists. 

Robert Wallace assisted in planning the curriculum. 

Financial support to the fledgling school was provided 

by USAID. The school has flourished, and its graduates 

are now employed in many places in Central America. 

They are available to work with technical specialists 

from the USGS and from other foreign countries to 

further develop their skills in exploring for and evaluating 

resources in their own countries. 

In 1968, D.E. White, in collaboration with a United 

Nations team and the Comision E jecutive H idroelectrica 

del Lempa, investigated the geothermal resources of El 

Salvador. The work also entailed establishing a geochemical laboratory. In the same year, White visited 

Nicaragua as part of a US AID project to work with the 

Servicio Geologico deN icaragua in evaluating proposals 

for a feasibility study on producing electricity geothermally. These cooperative investigations led to the completion of the El Salvador commercial geothermal electric plant, the first in Central America, and to further 

exploration and drilling of a favorable site inN icaragua. 

After the 1972 earthquake that destroyed the heart 

of Managua, Nicaragua, and an earlier earthquake in the 

suburbs of that city in 1968, USGS sent a team of 

earthquake specialists to study :earthquake _phenomena and to advise on geologic conditions that would 
have to be considered in planning reconstruction to minimize the damage from future earthquakes. A subsequent 

project established and equipped a Center for Earthquake 

Hazard Reduction and trained a staff for the center. 

Technical assistance to this endeavor continued into 

1977. 

In 1976, USGS made geologic and engineering 

studies of the February 4, 1976, earthquake in Guatemala, which caused extensive damage to buildings over 

a wide area owing to faulting, ground failure, and landslides. The effort was directed toward lessening the impact of inevitable future earthquakes. 

Currently, USGS is involved in a coal-resources 

program in Costa Rica sponsored by US AID, in earthquake-monitoring programs in Panama, Guatemala, 

and El Salvador, also sponsored by USAID, and in 

consultations relative to other possible projects in Central America. 

BIBLIOGRAPHY 

BELIZE 

Halley, R.B.. Shinn. E.A., Hudson, J.H., and Lidz, Barbara, 1977, 

Recent and relict topography of Boo Bee Patch reef, Belize. in 

International Coral Reef Symposium, 3d. May 1977, Proceedings: Miami, Rosensteel School of Marine and Atmospheric 

Sciences, University of Miami, p. 29~35. 

CENTRAL AMERICA 

Cathcart, J.B., 1977. Distribution and resources of phosphate in the 

eastern United States and Latin America. in Raup. O.B., ed., 

Proceedings of the Geology and Food Conference, with related 

U.S. Geological Survey projects and a bibliography: U.S. Geological Survey Circular 768, p. 3~7. 

Carter, W.O .. and Rinker, J.N., 1976, Structural features related to 

earthquakes, in Managua. Nicaragua, and Cordoba. Mexico, in 

Williams. R.S., Jr., and Carter, W.O., eds., ERTS~I, a new 

window on our planet: U.S. Geological Survey Professional 

Paper 929, p. 123~126. 

Case. J.E., and Holcombe, T.L., 1980, Geologic-tectonic map of the 

Caribbean region: U.S. Geological Survey Miscellaneous Investigations Map 1~1100, scale I :2,500,000. 

Drummond, K .J ., 1981, Plate-tectonic map of the circum-Pacific 

region, northeast quadrant: Tulsa, American Association of Petroleum Geologists, scale I : I 0,000,000. 

Erickson, R.L., compiler, 1982, Characteristics of mineral deposit 

occurrences: U.S. Geological Survey Open-File Report 82~795, 

227 p. 

Espinosa, A.F., 1982, Introduction: Seismology and earthquake engineering in Mexico and Central and South America: U.S. Geological Survey Earthquake Information Bulletin, v. 14, no. I, p. 4~6. 

___ 1983, Introduction: Seismology and earthquake engineering in 

Central and South America: U.S. Geological Survey Earthquake 

Information Bulletin, v. 15, no. I, p. 4--6. 

Grossling, B.F., 1975, Latin America's petroleum prospects in the 

energy crisis: U.S. Geological Survey Bulletin 1411, 40 p. 

36 

Guild, P.W., 1981a, A preliminary metallogenic map of North America: 

A numerical listing of deposits: U.S. Geological Survey Circular 

858~A. p. AI~A93. 

__ 1981b, Preliminary metallogenic map of North America: An 

alphabetical listing of deposits: U.S. Geological Survey Circular 

858~B, p. BI~B72. 

Klemic, H .. 1970, Iron ore deposits of the United States of America, 

Puerto Rico, Mexico, and Central America, in Survey of world 

iron ore resources: New York, United Nations, p. 411-477. 

Miller, R.L.. 1976, Potencial de los minerales industriales en Centroamerica: Instituto Centroamericano de I nvestigacion y Technologia Industrial Publicacion Geologicas, no. 5, p. 180~184. 

North American Metallogenic Map Committee, 1981, Metallogenic 

map of North America: Reston, Va., U.S. Geological Survey, 

scale I :500,000,000. 

Olive. W.W., 1978. Coal deposits of Latin America, in Kottlowski, 

F.E., Cross, A.T., and Meyerhoff, A.A., eds., Coal resources of 

the Americas, selected papers: Geological Society of America 

Special Paper 179, p. 57--64. 

Patterson, S.H .. 1967, Bauxite reserves and potential aluminum resources of the world: U.S. Geological Survey Bulletin 1228, 176 p. 

Quesada, Antonio, 1982, The role of the Organization of Latin American States in the development of seismology in Latin America: 

U.S. Geological Survey Earthquake Information Bulletin, v. 14, 

no. I, p. 7---:9. 

Roberts, R.J., and Irving, E.M., 1957, Mineral deposits of Central 

America, with a section on Manganese deposits of Panama, by 

F.S. Simons: U.S. Geological Survey Bulletin 1034,205 p .• 16 pis., 

15 figs. 

COSTA RICA 

Castillo M., Rolando, and Krushensky, R.D., 1977, Geologic 

map ofthe A bra quadrangle, Costa Rica: U.S. Geological Survey 

Miscellaneous Investigations Map 1~992, scale I :50,000. 

Gawarecki, S.J., Moxham, R.M., Morgan. J.O., and Parker, D.C., 

1980, An infrared survey of Irazu and vicinity, Costa Rica, in 

International Symposium on Remote Sensing of Environment, 

14th. San Jose, Costa Rica, Aprill980, Proceedings: Ann Arbor, 

Environmental Research Institute of Michigan, p. 1901~1912. 

Gutierrez, J .A., 1982, Earthquake engineering activities in Costa Rica: 

A review: U.S. Geological Survey Earthquake Information Bulletin, v. 14. no. I, p. 26~29. 

Krushensky, R.D., 1969, Geology of the Reventado River Watershed, 

Costa Rica, pt. A, General geology: U.S. Geological Survey 

Open-File Report (IR)CR~9, 19 p., I pl., I fig. 

__ 1972 [1973], Geology of the Istaru quadrangle, Costa Rica: 

U.S. Geological Survey Bulletin 1358, 46 p., 2 pis., I table. 

Krushensky, R.D., and Escalante, Gregorio, 1967, Activity of Irazu 

and Poas Volcanoes, Costa Rica. November 1964~July 1965: 

Bulletin Volcanologique, v. 31, p. 75~84. 

Krushensky, R.D., Malavassi V., Enrique, and Castillo M., Rolando, 

1976. Geology of central Costa Rica and its implications in the 

geologic history of the region: U.S. Geological Survey Journa!of 

Research, v. 4, no. 2, 127~134. 

__ 1976, Reconnaissance geologic map and cross sections of central Costa Rica: U.S. Geological Survey Miscellaneous Investigations Map 1~899, scale I: 100,000. 

Montero, WaY,er, 1983, Seismological program in Costa Rica: U.S. 

Geological Survey Earthquake Information Bulletin, v. 15, no. I, 

p. 7~10. 

Plafker, George, 1973a, Field reconnaissance of the effects of the 

earthquake of Aprill3, 1973. near Laguna de Arena!, Costa Rica: 
Seismological Society of America Bulletin, v. 63, no. 5, p. 

1847-1856. 

__ l973b, Field reconnaissance of the effects ofthe earthquake of 

Aprill3, 1973, near Laguna de Arenal, Costa Rica: U.S. Geological Survey Open-File Report (IR)CR-6, 17 . , 2 figs. 

Roberts, R.J ., 1944, Manganese deposits in Costa Rica: U.S. Geological Survey Bulletin 935-H, p. H387-H414, figs. 21-30, pis. 78-80. 

Waldron, H.H., 1965, Mudflows and floods in the Rio Reventado 

caused by eruption of Irazu Volcano, central Costa Rica [abs.]: 

Reunion de Geologos de Instituciones Gubernamentales de Centro America y Panama, 1st, San Jose, Costa Rica, 1965, Proceedings: 2 p. 

___ 1967, Debris flow and erosion control problems caused by the 

ash eruption of Irazu Volcano, Costa Rica: U.S. Geological Survey Bulletin 1241-1, 37 p. 

EL SALVADOR 

Aleman, C., 1943, Report relative to the present water service of 

Tonacetepeque, El Salvador: U.S. Geological Survey Open-File 

Report, 3 p. 

Argenal, Roger. 1983, Seismology in Nicaragua: U.S. Geological Survey Earthquake Information Bulletin, v. 15, no. 1, p. 23-27. 

Bundesanstalt fur Geowissenschaften und Rohstoffe, 1976-1978, 

Mapa geologico de Ia Republica de El Salvador/ America Central: Hannover, scale 1: I 00,000. 

Hoblitt, R.P., 1983, Volcanic events at a classic Mayan archaeological 

site near Joya de Ceren, El Salvador: Pennsylvania State University Occasional Publications in Anthropology [in press]. 

Martinez. M.A., 1982, Progress of the seismological program in El 

Salvador: U.S. Geological Survey Earthquake Information Bulletin, v. 14. no. I, p. 39-43. 

Pacheco, Mario, 1943a, A water supply for California, El Salvador: 

U.S. Geological Survey Open-File Report, 4 p. 

___ 1943 b, Report concerning the water service of J ocoro, El Salvador: U.S. Geological Survey Open-File Report, 4 p. 

___ 1943c, The water service of La Libertad, El Salvador: U.S. Geological Survey Open-File Report, 7 p., I fig. 

___ 1943d, Recommendations for improving the water services of 

Jucuapa, El Salvador, Central America: U.S. Geological Survey 

Open-File Report, 4 p. 

___ 1943e, Memorandum concerning the water supply of Mejicanos, El Salvador, and recommendations for improving it: U.S. 

Geological Survey Open-File Report, 7 p., 3 figs. 

___ 1943f, Report concerning the water supply in Quezaltepeque, 

El Salvador: U.S. Geological Survey Open-File Report, 7 p., 1 fig. 

___ 1943g, A water supply for San Carlos, El Salvador: U.S. Geological Survey Open-File Report, 3 p. 

___ 1943h, The municipal water service in San Julian. El Salvador: 

U.S. Geological Survey Open-File Report, 4 p. 

___ 1943i, Report relative to the improvement of the water services 

of San Vicente, El Salvador: U.S. Geological Survey Open-File 

Report, 8 p., I fig. 

___ 1943j, Report relative to the water service in Sensuntepeque, El 

Salvador: U.S. Geological Survey Open-File Report, 6 p., I fig. 

___ 1943k. Report concerning the water supply ofVilla Delgado, El 

Salvador, and recommendations for improving it: U.S. Geological Survey Open-File Report, 8 p. 

Sayre, A.N .. 1943a, Memorandum regarding an improved water supply 

for the city of Cojutepeque, El Salvador: U.S. Geological Survey 

Open-File Report, 5 p. 

___ 1943b, Memorandum concerning the possibility of obtaining a 

suitable water supply at a proposed rastro at Prusia, EI Salvador: 

U.S. Geological Survey Open-File Report, 5 p. 

37 

___ 1943c, Memorandum regarding the water supply of U sulutan, 

El Salvador: U.S. Geological Survey Open-File Report, 4 p. 

___ 1943d, Memorandum concerning the water supply at Zacatecoluca, El Salvador: U.S. Geological Survey Open-File Report, 

4 p. 

Sayre, A.N., and Taylor, G.C.,Jr., 1943, Water supplies at Santa Rosa, 

El Salvador: U.S. Geological Survey Open-File Report, 5 p. 

Sayre, A.N., and Taylor, G.C., Jr., 1951, Ground-water resources of 

the Republic of El Salvador, Central America: U.S. Geological 

Survey Water Supply Paper 1079-D, p. 0155-0225. 

Taylor. G.C., Jr., 1943a, Municipal water supply at Ahuachapan, El 

Salvador: U.S. Geological Survey Open-File Report, 5 p. 

___ 1943b, Water supply of Antiguo Cuscatlan, EI Salvador: U.S. 

Geological Survey Open-File Report, 4 p. 

___ 1943c, An improved municipal water supply at Armenia, El 

Salvador: U.S. Geological Survey Open-File Report, 5 p. 

___ 1943d, Municipal water supply at Atiquizaya, El Salvador: 

U.S. Geological Survey Open-File Report, 3 p. 

__ 1943e, An improved water supply for Chapeltique, El Salvador: 

U.S. Geological Survey Open-File Report, 3 p. 

___ 1943f, A water supply for EI Chilametal, El Salvador: U.S. 

Geological Survey Open-File Report, 6 p. 

___ 1943g. A water supply for El Refugio, El Salvador: U.S. Geological Survey Open-File Report, 4 p. 

__ l943h, Water supply at El Triunfo, El Salvador: U.S. Geological Survey Open-File Report, 6 p., 5 figs. 

__ 1943i, Conditions of water supply at Guadalupe, El Salvador: 

U.S. Geological Survey Open-File Report, 4 p., 1 fig. 

__ 1943j, Recommendations for improving water supplies at 

Jiquilisco, El Salvador: U.S. Geological Survey Open-File Report, 

4 p. 

___ l943k, A water supply at Nueva Granda, El Salvador: U.S. 

Geological Survey Open-File Report, 4 p. 

___ 19431, A water supply at Panchimalco, El Salvador: U.S. Geological Survey Open-File Report. 4 p., 1 fig. 

___ l943m, The municipal water supply at San Francisco Gotera, 

El Salvador: U.S. Geological Survey Open-File Report, 5 p. 

___ l943n, An improved water supply for San Martin, EI Salvador, 

Central America: U.S. Geological Survey Open-File Report, 12 p. 

__ 1943o, Municipal water supply at Santa Tecla, El Salvador. 

Central America: U.S. Geological Survey Open-File Report, 12 p. 

___ 1943p, Water supplies at Tejutepeque, El Salvador: U.S. Geological Survey Open-File Report, 4 p., 2 figs. 

__ l943q, Water supply forTepetitan, El Salvador: U.S. Geological Survey Open-File Report, 4 p., 1 fig. 

___ 1943r, Water supply at Vera paz. El Salvador: U.S. Geological 

Survey Open-File Report, 4 p., 1 fig. 

___ l944a, Condition of ground-water occurence in the city of San 

Salvador, El Salvador, Central America: U.S. Geological Survey 

Open-File Report, 4 p. 

___ 1944b, Gravity water supplies of San Salvador: U.S. Geological 

Survey Open-File Report, 12 p. 

GUATEMALA 

Bucknam. R.C., 1977, Surface faulting and displacements of the 1976 

Guatemala earthquake: U.S. Geological Survey Earthquake 

Information Bulletin, v. 9, no. 2, p. 12-17. 

Espinosa, A. F .. 1977a, Intensity distribution of the Guatemala earthquake: U.S. Geological Survey Earthquake Information Bulletin, 

v. 9, no. 2, p. 7-11. 

___ l977b, The Guatemala earthquake of February 4, 1976: U.S. 

Geological Survey Earthquake Info!"mation Bulletin, v. 9, no. 

2, p. 4-6. 
___ 1977, ed., The Guatemalan earthquake of February 4, 1976, a 

preliminary report: U.S. Geological Survey Professional Paper 

1002, 90 p., 76 figs., II tables. 

Harp, E.L., Wieczorek, G.F., Wilson, R.C., and Fleming, R.W .. 1976, 

Seismic-induced landslides from the February 4, 1976, Guatemala 

earthquake [abs.]: Geological Society of America Abstracts with 

Programs, v. 8, no. 6, p. 905. 

Harp, E.L., Wilson, R.C., and Wieczorek, G.F., 1981, Landslides from 

the February 4, 1976, Guatemala earthquake: U.S. Geological 

Survey Professional Paper 1204-A, 35 p., 2 pis. 

Hoose, S.N., and Wilson, R.C., 1976, Liquefaction-caused ground 

failure during the Guatemala earthquake of February 4, 1976 

[abs.]: Geological Society of America Abstracts with Programs, v. 

8, no. 6, p. 925. 

Hoose, S.N., Wilson, R.C., and Rosenfeld, J.H., 1978, Liquefactioncaused ground failure during the February 4, 1976, Guatemala 

earthquake, in International Symposium on the February 4, 1976. 

Guatemalan Earthquake and Reconstruction Process, Proceedings: v. 2. 

Instituto Geografico Nacional de Guatemala, 1965-1969, Geologia del 

area, Republica de Guatemala: Guatemala City, scale I :250,000. 

___ 1966-1975, Mapa geologico de Guatemala: Guatemala City, 

scale I: 50,000. 

__ 1967, Mapa de Reconociemento geologico de Ia region de Ia 

Republica de Guatemala: Guatemala City, scale I: 125,000. 

Ladd, J.W., Ibrahim, A.K., McMillen, K.J., Latham, G.V., and Von 

Huene, R.E., 1978, Structures and tectonics associated with the 

Middle America trench offshore Guatemala [abs.]: Geological 

Society of America Abstracts with Programs, v. 10, no. 7, p. 439. 

Langer, C.J., Bollinger, G.A., and Henrisey, R.G., 1978, Aftershocks 

and secondary faulting associated with the February 4, 1976, 

Guatemala earthquake, in International Symposium on the February 4, 1976, Guatemalan Earthquake and the Reconstruction 

Process, Proceedings: v. 2. 

Miller, R.L., 1964, The minerals position of Guatemala in 1961, with 

special reference to industrial minerals: U.S. Geological Survey 

Open-File Report, 40 p., 2 figs., 5 tables. 

Page, R.A., ed., 1976, Interim report on the Guatemalan earthquake of 

February 4, 1976, and the activities of the U.S. Geological Survey 

earthquake investigation team: U.S. Geological Survey Open-File 

Report 76-295, 31 p., 4 figs. 

Plafker, George, 1977, The Guatemala earthquake and Caribbean plate 

tectonics: U.S. Geological Survey Earthquake Information Bulletin, v. 9, no. 2, p. 18-20. 

Plafker, George, Sharp, R.V., Bucknam, R.C., Bonis, S.B., and Bonilla, 

M.G., 1976, Tectonic implications of surface faulting associated 

with the4 February 1976 Guatemaleearthquake [abs.]: Geological Society of America Abstracts with Programs, v. 8, no. 6, p. 

1051. 

Rose, W.I., Jr., Cadle, R.O., Heidt, L.E., Friedman. Irving, Lazrus, 

A.L., and Huebert, B.J ., 1980, Gas and hydrogen isotopic analyses of volcanic eruption clouds in Guatemala sampled by aircraft: 

Volcanology and Geothermal Research Journal. v. 7. p. 1-10. 

Schwartz, D.P., 1976, The Motagua fault zone, Guatemala [abs.]: 

Geological Society of America Abstracts with Programs, v. 8. no. 

6, p. 1092. 

White, R.A., and Harlow, D.H., 1979, Preliminary catalog of aftershocks of the Guatemala earthquake ofF ebruary 4, 1976-from 

the area between Guatemala City and Lake A titian: U.S. Geological Survey Open-File Report 79-864, 63 p. 

___ 1980, Preliminary catalog of seismicity from south-central 

Guatemala, July I through December 31, 1976: U.S. Geological 

Survey Open-File Report 80-83, 39 p. 

38 

White, R.A., Sanchez, Eddy, Cifuentes, I.L., and Harlow, D. H., 1980, 

Preliminary report to the government of Guatemala on the ongoing earthquake swarm in the Department of Santa Rosa, Guatemala (translated from the original Spanish): U.S. Geological Survey Open-File Report 80-900, 24 p. 

NICARAGUA 

Brown, R.P., Ward, P.L., and Plafker, George, 1973, Geologic and 

seismologic aspects of the Managua, Nicaragua, earthquake of 

Dec. 23, 1972: U.S. Geological Survey Professional Paper 838, 34 

p., 23 figs. 

Carter, W.O., and Eaton, G.P., 1973, ERTS-1 image contributes to 

understanding of geologic structures related to the 1972 Managua 

earthquake, in National Aeronautics and Space Administration 

Symposium on Significant Results Obtained from ERTS-1, 

March 5-9, 1973, New Carrollton, Md.: NASA Special Publication 327, p. 459-471. 

Husid, R., and Espinosa, A.F., 1975, Seismological and engineering 

aspects of the March 6, 1974, Carazo earthquake [Nicaragua], in 

European Conference on Earthquake Engineering, 5th, Istanbul 

1975, Proceedings: v. 2, chap. 7, paper 137, 4 p. 

Krushensky, R.D., Schmoll, H.R., and Dobrovolny, Ernest, 1975, The 

1972 Managua earthquake: Geologic constraints on planning for 

the reconstruction or relocation of Managua, Nicaragua, in 

Caribbean Geological Conference, 7th, Martinique and Guadaloupe, French Antilles, 1974, Transactions: p. 610-614. 

Martinez, H., M.A., and Kuang S., Juan, 1973, Mapa geologico preliminar, Republica de Nicaragua: Nicaragua Instituto Geografico 

Nacional, scale I: I ,000,000. 

Sayre, A.N., 1943, Memorandum concerning proposed water supply 

development at Lake Tiscapa, Managua, Nicaragua: U.S. Geological Survey Open-File Report, 9 p. 

Schmoll, H.R., Krushensky. R.D., and Dobrovolny, Ernest, 1973, 

Geologic constraints on planning for redevelopment of Managua, 

Nicaragua, following the 1972 earthquake: U.S. Geological Survey Open-File Report (IR)NI-2, 79 p., I pl., 8 figs .. 2 tables. 

___ 1975, Geologic considerations for redevelopment planning of 

Managua, Nicaragua, following the 1972 earthquake: U.S. Geological Survey Professional Paper 914, 23 p., I pl., 8 figs. 

Schoff, S. L., l956a, Ground water for irrigation at La Calera, 

Nicaragua: U.S. Geological Survey Open-File Report, 7 p. 

___ 1956b, Ground-water data, Nicaragua: U.S. Geological 

Survey Open-File Report, 25 p., 4 figs., 2 maps. 

Taylor, G.C., Jr., 1943, Conditions of ground-water on the plateau of 

La Sierras, Nicaragua: U.S. Geological Survey Open-File Report, 

3 p. 

PANAMA 

Direccion General de Recursos M inerales, 1976, Mapa geologico, 

Republica de Panama: Panama Ministerio de Comercio e Industrias, scale I : I ,000,000. 

Larocque, J .. Metti, A., Recchi, G., Roquebert J., Stewart, R., del 

Giudice, D., Esquivel, D., Lovell, J., Luque, V., Merida, A., and 

Torre, F., 1972, Mapa geologico preliminar, Republica de 

Panama: Panama Direccion General de Recursos Minerales, 

Ministerio de Comercio e lndustrias Open-File Map, scale 

I: I ,000,000. 

Simons, F.S., 1951, Some manganese deposits in the Republic of Panama: U.S. Geological Survey Open-File Report. 61 p., 12 figs. 

Stewart, R.H., and Woodring, W.P., 1980, Geologic map of the 

Panama Canal and vicinity, Republic of Panama: U.S. Geological Survey Miscellaneous Investigations Map 1-1232, scale 

I: 100,000. 
Taylor, G.C., Jr., 1949, Ground water in Herrera Province and adjoining areas in Code, Los Santos, and Veraguas Provinces, Panama: 

U.S. Geological Survey Open-File Report, 20 p., I pl., 2 figs. 

Woodring, W.P., 1957, Geology and paleontology of Canal Zone and 

adjoining parts of Panama: Geology and description of Tertiary 

mollusks (Gastropods: Trochidae to Turritellidae): U.S. Geological Survey Professional Paper 306-A, 145 p., 23 pis., 4 figs. 

Woodring, W.P., and Thompson, T.F., 1949, Tertiary formations of 

Panama Canal Zone adjoining parts of Panama: American Association of Petroleum Geologists Bulletin. v. 33, no. 2, p. 223-247. 

APPENDIX 2.-EARTH-SCIENCE AGENCIES IN CENTRAL AMERICAN COUNTRIES 

BELIZE 

Ministry of Natural Resources 

Belmopan 

Ministry of Energy and Communications 

Belmopan 

National Water and Sewer Authority 

National Meteorological Service 

Ministry of Energy and Communications 

Belize International Airport 

Belize City 

COSTA RICA 

Departamento de Geologia 

Instituto Costarricense de E!ectricidad (ICE) 

Apartado 10032 

San Jose 

Departamento de Desarrollo Geologico y Recursos Minerales 

Corporacion Costarricense de Desarrollo (CODESA) 

A partado I 0323 

San Jose 

I nstituto Geografico N acional 

A partado 2272 

San Jose 

Departamento de £studios B~sicos 

lnstituto Costarricense de Electricidad 

P.O. Box 10032 

San Jose 

Servicio Nacional de Aguas Subterraneas (SEN AS) 

Apartado 5262 

San Jose 

Direccion de Geologia, Minas y Petroleo 

M inisterio de Economia e Industria 

A partado 10216 

San Jose 

Refinadora Costarricense de Petroleo 

Direccion de Recursos Carboniferos 

P.O. Box 4351 

San Jose 

EL SALVADOR 

Centro de Investigaciones Geotecnicas 

Ministerio de Obras Publicas 

Avenida Peralta, final, costado Oriente Talleres El Coro 

San Salvador 

39 

Comision Ejecutiva Hidroelectrica del Rio Lempa 

9 Calla Poniente, #950 

Centro de Gobierno 

San Salvador 

Comision Nacional del Petroleo 

M inisterio de Economia 

3a Calle Poniente 1225 

San Salvador 

Instituto Geografico Nacional "lngeniero Pablo Arnoldo Guzman" 

Ministerio de Obras Publicas 

Avenida Juan Bertis No. 79 

San Salvador 

Ministerio de Obras Publicas 

Palacio N acional 

San Salvador 

Direccion General de Riego y Dranaje 

Ministerio de Agricultura y Ganaderia 

Nueva San Salvador 

Servicio Hidrologico 

Direccion General de Recursos Naturales Renovables 

Canton El Matasano 

Soyapango 

Servicio Meteorologico Nacional 

Ministerio de Agricultura y Ganaderia 

Nueva San Salvador 

M inisterio de Agricultura y Ganaderia 

Boulevard Los Heroes y 21 Calle Poniente 

San Salvador 

GUATEMALA 

Instituto de Sismologia, Vulcanologia, Meteorologia, e Hidrologia 

(INSIVUMEH) 

7 Avenida 14-47, Zona 13 

Guatemala City 

Division de Geologia 

Instituto Geografico Nacional 

A venida las Americas 5-76, Zona 13 

Guatemala City 

Ministeria de Energia y Mineria 

Diagonal I7 entre 20 y 30 Calles, Zona II 

Guatemala City 
0 bservatorio N acional 

La Aurora, Zona 13 

Guatemala City 

I nstituto Geografico N acional 

A venida de las Americas 5-76, Zona 13 

Guatemala City 

HONDURAS 

Exploracion Geotermica 

Empresa Nacional de Energia Electrica (ENEE) 

Apartado 99 

Tegucigalpa, D.C. 

Direccion General de Minas e Hidrocarburos 

M inisterio de Recursos Naturales 

Boulevard Centro America 

Tegucigalpa, D.C. 

Servicio Autonomo Nacional de Acueductos y Alcantarillados 

(SANAA) 

Apartado Postal 437 

Tegucigalpa, D.C. 

Servicios H idrologicos y Climatologicos 

M inisterio de Recursos Naturales 

Apartado 1839 

Tegucigalpa, D.C. 

Instituto Geografico Nacional (IGN) 

Apartado Postal 758 

Barrio La Balsa 

Comayaguela D.C. 

Oficina Nacional de Programa Catastral 

Edificio Didemo, 4 Piso 

Tegucigalpa, D.C. 

Comision Nacional de Energia 

Ministerio de Economia y Comercio 

Altos Edif. Banco de Londres y Montreal 

Tegucigalpa, D.C. 

NICARAGUA 

Proyecto Geotermico 

Instituto Nicaraguense de Energia 

Apartado 55 

Managua 

C orporacion N icaraguense de Minas e H idrocarbu ros (CONDE M I A) 

Apartado Postal No.8 

Managua, D.N. 

I nstituto N icaraguense de Recursos Naturales y del Ambiente (IRENA) 

Apartado Postal No. 5123 

Managua, D.N. 

lnstituto de Investigacion Sismica 

Apartado Postal No. 1761 

Managua, D.N. 

I nstituto Geografico N acional 

Ministerio de Fomento y Obras Publicas 

Apartado Postal2120 

Managua, D.N. 

PANAMA 

Administracion de Recursos Minerales 

Apartado Postal9658, Zona 4 

Panama City 

Corporacion de Desarrollo Minero-Cerro Colorado (CODEMIN) 

A partado 5312 

Panama 5 

lnstituto Geografico Nacional "Tommy Guardia" 

Apartado Postal 5267, Zona 5 

Panama City 

Instituto de Acueductos y Alcantarillados Nacionales (IDAAN) 

A partado 5234 

Panama 5 

lnstituto de Recursos Hidraulicos y Electrificacion (IRHE) 

Apartado 5285 

Panama 5 

Direccion de Recursos Naturales Renovables (RENARE) 

M inisterio de Desarrollo Agropecuario 

Santiago, Veraguas 

40