Middle America Trench: Acapulco and Guatemala Trenches (Central America)

Middle America Trench: Acapulco and Guatemala Trenches (Central America)

Thu, 09/23/2021 - 15:42

The Middle America Trench is a major subduction zone, an oceanic trench in the eastern Pacific Ocean off the coast of Central America. It can be divided into a northern section called the Acapulco Trench and a southern section called the Guatemala Trench.

Middle America Trench

The Middle America Trench, sometimes referred to as the Central America Trench or Mid-American Trench, is a major subduction zone, an oceanic trench in the eastern Pacific Ocean off the coast of Central America. It can be divided into a northern section called the Acapulco Trench and a southern section called the Guatemala Trench.

Stretching from central Mexico to Costa Rica, the trench is approximately 2,750 km (1,700 mi) long. It reaches a depth of 6,689 m (21,880 ft) at its deepest point; the 18th-deepest trench in the world. It covers a total area of 96,000 aq km (37,000 sq mi).

The trench is the boundary between the Rivera Plate (a microplate), the Cocos Plate and the Nazca Plate on one side; and the North American Plate and Caribbean Plate on the other. Many large earthquakes have occurred in the area of the Middle America Trench.

Tectonic setting of Midle American Trench

Map depicting the tectonic setting of the Middle American Trench off western Mexico

Acapulco Trench / Guatemala Trench

The Middle America Trench can be divided into northern and southern sections. The division, however, is not the same in its seaward side and its landward side.

On the seaward side, the northern section, called the Acapulco Trench, runs from Jalisco to the Tehuantepec Ridge and follows a general curve that mimics the Mexican coast. It is bordered by the Tamayo Transform Fault, which is part of the East Pacific Rise.

The southern section, called the Guatemala Trench, follows a near-linear course that runs from the Tehuantepec Ridge off the Mexican coast to the Cocos Ridge off Costa Rica.

On the landward side, the division is demarcated along the Polochic-Motagua fault system which is the boundary between the North American Plate and the Caribbean Plate. The dividing point on the landward side is about 400 km (250 mi) east of that on the seaward side.

The southern section of the trench is usually associated with active volcanism on land.

The Central American volcanic arc with the Mid-American trench to the southwest.

Map depicting the Central American Volcanic Arc with the Middle American Trench to the southwest