El Salvador, the smallest Spanish-speaking nation in the Western
Hemisphere, is located on the western side of the Central American
isthmus. With an area of 21,041 square kilometers, the country is only
slightly larger than Massachusetts. It is roughly rectangular in shape
with 515 kilometers of land boundaries and 307 kilometers of coastline
on the Pacific Ocean. El Salvador is bounded by Guatemala to the west
and Honduras to the north and east, and it is separated from Nicaragua
on the southeast by the Golfo de Fonseca.
Geology
El Salvador, along with the rest of Middle America (a region
comprising mainly Mexico and Central America), is one of the most
seismologically active regions on earth, situated atop three of the
large tectonic plates that constitute the earth's surface. The motion of
these plates causes the area's earthquake and volcanic activity.
Most of Central America and the Caribbean Basin rests on the
relatively motionless Caribbean Plate. The Pacific Ocean floor, however,
is being carried northeast by the underlying motion of the Cocos Plate.
Ocean floor material is relatively dense; when it strikes the lighter
granite rocks of Central America, the ocean floor is forced down under
the land mass, creating the deep Middle America Trench that lies off the
coast of El Salvador. The subduction of the Cocos Plate accounts for the
frequency of earthquakes near the coast. As the rocks constituting the
ocean floor are forced down, they melt, and the molten material pours up
through weaknesses in the surface rock, producing volcanoes and geysers.
North of El Salvador, Mexico and most of Guatemala are riding on the
westward-moving North American Plate that butts against the northern
edge of the stationary Caribbean Plate in southern Guatemala. The
grinding action of these two plates creates a fault, similar to the San
Andreas in California, that runs the length of the valley of the Rio
Motagua in Guatemala. Motion along this fault is the source of
earthquakes in northernmost El Salvador.
El Salvador has a long history of destructive earthquakes and
volcanic eruptions. San Salvador was destroyed in 1756 and 1854, and it
suffered heavy damage in the 1919, 1982, and 1986 tremors. The country
has over twenty volcanoes, although only two, San Miguel and Izalco,
have been active in recent years. Violent eruptions are rare. From the
early nineteenth century to the mid1950s , Izalco erupted with a
regularity that earned it the name "Lighthouse of the
Pacific." Its brilliant flares were clearly visible for great
distances at sea, and at night its glowing lava turned it into a
brilliant luminous cone.
<>Physical
Features
Two parallel mountain ranges cross El Salvador east to west with a
central plateau between them and a narrow coastal plain hugging the
Pacific. These physical features divide the country into two
physiographic regions. The mountain ranges and central plateau covering
85 percent of the land comprise the interior highlands. The remaining
coastal plains are referred to as the Pacific lowlands.
The northern range of mountains, the Sierra Madre, forms a continuous
chain along the border with Honduras. Elevations in this region range
from 1,600 to 2,200 meters. The area was once heavily forested, but
overexploitation led to extensive erosion, and it has become semibarren.
As a result, it is the country's most sparsely populated zone, with
little farming or other development.
The southern range of mountains is actually a discontinuous chain of
more than twenty volcanoes, clustered into five groups. The westernmost
group, near the Guatemalan border, contains Izalco and Santa Ana, which
at 2,365 meters is the highest point in El Salvador. Between the cones
lie alluvial basins and rolling hills eroded from ash deposits. The
volcanic soil is rich, and much of El Salvador's coffee is planted on
these slopes.
The central plateau constitutes only 25 percent of the land area but
contains the heaviest concentration of population and the country's
largest cities. This plain is about 50 kilometers wide and has an
average elevation of 600 meters. Terrain here is rolling, with
occasional escarpments, lava fields, and geysers.
A narrow plain extends from the coastal volcanic range to the Pacific
Ocean. This region has a width ranging from one to thirty-two kilometers
with the widest section in the east, adjacent to the Golfo de Fonseca.
Near La Libertad, however, the mountains pinch the lowlands out; the
slopes of adjacent volcanoes come down directly to the sea. Surfaces in
the Pacific lowlands are generally flat or gently rolling and result
from alluvial deposits from nearby slopes.
El Salvador has over 300 rivers, the most important of which is the
Rio Lempa. Originating in Guatemala, the Rio Lempa cuts across the
northern range of mountains, flows along much of the central plateau,
and finally cuts through the southern volcanic range to empty into the
Pacific. It is El Salvador's only navigable river, and it and its
tributaries drain about half the country. Other rivers are generally
short and drain the Pacific lowlands or flow from the central plateau
through gaps in the southern mountain range to the Pacific.
Numerous lakes of volcanic origin are found in the interior
highlands; many of these lakes are surrounded by mountains and have
high, steep banks. The largest lake, the Lago de Ilopango, lies just to
the east of the capital. Other large lakes include the Lago de
Coatepeque in the west and the Lago de G�ija on the Guatemalan border.
The Cerron Grande Dam on the Rio Lempa has created a large reservoir,
the Embalse Cerron Grande, in northern El Salvador.
El Salvador - Climate
El Salvador has a tropical climate with pronounced wet and dry
seasons. Temperatures vary primarily with elevation and show little
seasonal change. The Pacific lowlands are uniformly hot; the central
plateau and mountain areas are more moderate.
The rainy season, known locally as invierno, or winter,
extends from May to October. Almost all the annual rainfall occurs
during this time, and yearly totals, particularly on southern-facing
mountain slopes, can be as high as 200 centimeters. Protected areas and
the central plateau receive lesser, although still significant, amounts.
Rainfall during this season generally comes from low pressure over the
Pacific and usually falls in heavy afternoon thunderstorms. Although
hurricanes occasionally form in the Pacific, they seldom affect El
Salvador.
From November through April, the northeast trade winds control
weather patterns. During these months, air flowing from the Caribbean
has had most of the precipitation wrung out of it passing over the
mountains in Honduras. By the time this air reaches El Salvador, it is
dry, hot, and hazy. This season is known locally as verano, or
summer.
Temperatures vary little with season; elevation is the primary
determinant. The Pacific lowlands are the hottest region, with annual
averages ranging from 25�C to 29�C. San Salvador is representative of
the central plateau, with an annual average temperature of 23�C and
absolute high and low readings of 38�C and 7�C, respectively. Mountain
areas are the coolest, with annual averages from 12�C to 23�C and
minimum temperatures sometimes approaching freezing.
