Highest Mountains in Mexico

Geography

Pico de Orizaba is located at 19°1′48″N 97°16′12″W, about 110 kilometres (68 mi) west of the Gulf of Mexico and 200 kilometres (120 mi) east of Mexico City, on the border between the states of Veracruz and Puebla. The volcano is approximately 480 kilometres (300 mi) south of the Tropic of Cancer. Orizaba anchors the south-eastern end of the Trans-Mexican Volcanic Belt, a volcanic chain that runs from west to east across Central Mexico. A companion peak lying about six km to the southwest of Pico de Orizaba is the Sierra Negra, at 4,640 metres (15,223 ft). This subsidiary peak is significantly lower than its massive neighbour, but the road to the observatory on its summit is the highest road in North America.

Geology

Pico de Orizaba evolved in three stages, the most recent initiated about 16,000 years ago during the late Pleistocene and Holocene. Citlaltépetl consists of three superimposed stratovolcanoes and dome intrusions: Torrecillas (650–250 ka), Espolón de Oro (210– 16 ka), and Citlaltépetl (16 ka to present). The volcano was formed by thick andesitic and dacitic lavas that followed repetitive explosive eruptions and lava effusions that created the iconic cone structure. The volcano is currently dormant but not extinct. The latest eruption of the volcano occurred in 1846 with a magnitude of VEI 2.

History

Pico de Orizaba was important in pre-Hispanic cultures, such as those of the Nahuatl-speaking Mexica and the Totonacs. The volcano is part of many native mythologies, defining Nahua folklore, cosmology, and eschatology.

During the Spanish Conquest of Mexico, Hernán Cortés passed through the foothills of Pico de Orizaba; the volcano and the surrounding mountains made his journey to Tenochtitlan more difficult and delayed him for many days. During the 1600s, the Spanish Crown financed several roads to be built that would circumvent Citlaltépetl. One of the roads was routed south of the volcano through the cities of Orizaba and Fortín de las Flores, which became the main trade route between Mexico City and Veracruz on the Gulf Coast.

Climate

The climate of Pico de Orizaba, like the Sierra Madre Oriental, varies greatly due to the change of elevation and prevailing winds. Due to the latitude and the extreme rugged terrain the volcano experiences many microclimates. Vegetation varies from tropical at the lower elevations on the eastern face to alpine forests in the higher elevations.

Large amounts of precipitation fall on the eastern face of the volcano due to adiabatic cooling and condensation from the trade winds that bring moisture off the Gulf of Mexico. The eastern face is frequently covered by fog and low cloud cover.

Geology

The stratovolcano contains a steep-walled, 400 m × 600 m (1,300 ft × 2,000 ft) wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris avalanche deposits covering broad areas south of the volcano. The modern volcano was constructed to the south of the late-Pleistocene to Holocene El Fraile cone. Three major Plinian eruptions, the most recent of which took place about 800 AD, have occurred from Popocatépetl since the mid-Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano.

History

The geological history of Popocatépetl began with the formation of the ancestral volcano Nexpayantla. About 200,000 years ago, Nexpayantla collapsed in an eruption, leaving a caldera in which the next volcano, known as El Fraile, began to form. Another eruption about 50,000 years ago caused that to collapse, and Popocatépetl rose from that. Around 23,000 years ago, a lateral eruption (believed to be larger than the 1980 eruption of Mount St. Helens) destroyed the volcano's ancient cone and created an avalanche that reached up to 70 kilometres (43 mi) from the summit. The debris field from that is one of four around the volcano, and it is also the youngest.

Geological history

In the late Pleistocene era, a huge landslide occurred at the mountain, with approximately 25 km3 (6.0 mi3) of debris traveling some 120 km, reaching the Pacific Ocean. An area of some 2,200 km2 was covered in landslide deposits. The currently active cone is within a large caldera that was probably formed by a combination of landslides and large eruptions. The lava is andesite containing 56-61% SiO2. About 300,000 people live within 40 km (25 mi) of the volcano, which makes it the most dangerous volcano in Mexico. In light of its history of large eruptions and situation in a densely populated area, it was designated a Decade Volcano, singling it out for study.

Geography

The volcano is located within the Tacaná municipality of the San Marcos Department in Guatemala; and within the Cacahoatán and Unión Juárez Municipalities of Chiapas state in Mexico.

Its last known eruption was registered in 1986 — a small phreatic eruption in May — but it is still considered as dangerous to more than 250,000 people residing in the area.

Tacaná is the first of hundreds of volcanoes in a 1,500 km (930 mi) km row, arranged NW to SE, parallel to the Pacific Ocean coast of Central America, known as the Central America Volcanic Arc, formed by an active subduction zone along the western boundary of the Caribbean Plate.

The agricultural valley at its NNE foothills is covered with thick deposits of lahars.

Geology

The mountain began to form during Paleogene geologic period characterized by intense volcanic activity in the area throwing lava and ash onto the surrounding plateau and creating the Sierra Madre Occidental. Cerro Mohinora was raised to an elevation over 3,300 m above sea level during the Pleistocene by intense tectonic activity. The mountain is mainly composed of igneous rock.

Climate

Using the Köppen climate classification the climate of the mountain is humid continental climate (Dfb). Summers are cool with temperatures rarely reaching 25 °C (77 °F) and summer lows fall below 10 °C (50 °F) regularly. There are heavy rainstorms from June to October. Winters are very cold with maximum high reaching 0 °C (32 °F) and reaching a maximum low of -31 °C (-24 °F). Winter snowstorms with high winds are common and typically over 1 meter (~3 ft) of snow per season.

Climate

The peak has either a cold-summer Mediterranean climate (Csc) or a Mediterranean-influenced subarctic climate (Dsc)in the Köppen climate classification depending whether the threshold for those climates is considered 0°C or -3°C.