How long is Mexico’s coastline?

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Sep 122016
 

This might seem like a very simple question to answer, but actually it is a question which has no definitive answer!

According to the CIA World Factbook, Mexico has 9,330 kilometers of coastline.

According to Mexico’s National Statistics Institute (INEGI), it has 11,122 kilometers of coastline, and that figure apparently excludes the coastlines of Mexico’s various islands.

Amazingly, it is perfectly possible that both figures are ‘correct’.

This is because the length of  a coastline depends in large part on the scale of the map used to make the measurements.  All maps are generalization of reality, and some are more generalized than others. Small-scale maps of Mexico fail to show every bay and headland; measurements made on them will invariably be under the true value. The larger the scale of the map, the closer the measurement will be to ‘reality’, because the map will show more indentations or tiny crenulations.

Theoretically (mathematically), is is  impossible to ever arrive at a definitive length for a coastline since the harder you look (the larger the scale of the map), the more you see, and this carries on indefinitely. This is why it is not at all surprising that different sources offer different distances for the length of Mexico’s coastline (or for particular rivers).

And the moral of this story? In geography, never assume that an apparently simple question has a simple answer!

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Video of the Sea of Cortés (Gulf of California)

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Aug 232016
 

This PostandFly video explores the islands of San Jose, San Francisco and Espiritu Santo. The Sea of Cortés (Gulf of California) is the body of water that separates the Baja California Peninsula from the Mexican mainland. The Sea of Cortés is thought to be one of the most diverse seas on the planet, and is home to more than 5,000 species of micro-invertebrates. A large part of the Sea of Cortés is a UNESCO World Heritage Site.

Several rivers feed the Sea of Cortés, including the Colorado, Fuerte and Yaqui. The Sea of Cortés has more than 300 estuaries and other wetlands on its shores, of which the delta of the Colorado River is especially important. The vast reduction in the Colorado’s flow has negatively impacted wetlands and fisheries.

Previous Geo-Mexico posts on this area of Mexico include:

Jan 112016
 

On 9 January 2016, the Google search pages in some countries (including the USA and Mexico but, curiously, not Canada) featured a Google Doodle about the amazing Monarch Butterflies. That day was exactly 41 years from when Ken Brugger and his partner Cathy Trail finally located the exact site of a major overwintering group of Monarch Butterflies in Mexico.

Their effort was part of the research led by Canadian zoologist Fred Urquhart to try to determine what happened to Canadian Monarch Butterflies during the winter. Urquhart knew they fluttered south, but just where did they all go? Urquhart and his team of helpers tagged thousands of butterflies, and gradually homed in on an area of western Mexico straddling the border between the state of México and the state of Michoacán.

Based on original map design created by Paul Mirocha (paulmirocha.com) for Monarch Watch.

Based on original map design created by Paul Mirocha (paulmirocha.com) for Monarch Watch.

It eventually emerged that there were several overwintering sites of Monarch Butterflies in that general area, and much of the zone is now formally protected, with strict conditions for visitors and restrictions on tree cutting and forest thinning.

The Monarch Butterfly overwintering sites are a fitting topic of a Google Doodle. Sadly, the paragraph explaining the Monarch Butterfly Google Doodle repeats a common error about Mexico’s geography, and one we have featured previously on this blog.

It places the Monarch Butterfly overwintering sites in “Mexico’s easternmost Sierra Madre Mountains”. Unfortunately, this phrase, even if oft-repeated on ill-informed websites, is far from true.

Location of Volcanic Axis and Monarch Butterfly reserves

Location of Volcanic Axis and Monarch Butterfly reserves. Basemap: Figure 3.1 of Geo-Mexico; all rights reserved.

Mexico has three major Sierra Madre ranges: The Western Sierra Madre, Eastern Sierra Madre and Southern Sierra Madre (see map). Mexico’s “easternmost Sierra Madre Mountains” would actually be the Southern Sierra Madre! The Monarch Butterfly reserves are not located in any of these three Sierra Madres; they are happily ensconced in the Volcanic Axis.

Given that Google is reported to be introducing some form of reliability factor into its search algorithms, lending more credence to sites that are “factually accurate” and supported by other sites, this begs the question as to whether the majority is necessarily always right. In this case, while there are numerous web references to the Monarch Butterflies hanging out in “Mexico’s Sierra Madre” mountains, they are all guilty of misrepresenting Mexico’s physical geography.

Geo-Mexico congratulates Google for choosing to feature the Monarch Butterfly and loves the title “Mountain of the Butterflies” but does hope that Google Doodle writers will check their information more carefully next time.

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Mexico’s scenery: spectacular aerial views

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Dec 102015
 

The award-winning video team at PostandFly.com.mx continue to produce some powerfully-evocative short videos focusing on Mexico’s extraordinary scenery.

Many of the individual clips in this video were filmed in Baja California Sur, with occasional forays into Chihuahua and central and southern Mexico:

For those that like to match names with places (that’s what makes you a geographer, right?), here is the list of places in order of their appearance in the video, with a few clues to act as “landmarks” along the way:

1Bacalar, Quintana Roo21Puerta del Cielo, Queretaro
2Isla Partida, Baja California Sur22Guerrero Negro, Baja California Sur
3Guerrero Negro, Baja California Sur23Playa Escondida, Nayarit
4Isla San José, Baja California Sur24Acapulco, Guerrero
5Bacalar, Quintana Roo25Isla San Francisquito, Baja California Sur
6San Ignacio, Baja California Sur26Isla Partida, Baja California Sur
7El Cielo, Tamaulipas27Basaseachi, Chihuahua [waterfall]
8Isla Partida, Baja California Sur28Xicotepec, Puebla
9Basaseachi, Chihuahua [waterfall]29Caleta y Caletilla, Acapulco, Guerrero
10Isla Coronado, Baja California Sur30Islas Marietas, Nayarit
11Isla Partida, Baja California Sur31Angel de la Independencia, Mexico City
12Basaseachi, Chihuahua [waterfall]32Puerto Vallarta, Jalisco
13Punta Colorada, Baja California Sur33Estrella de Puebla, Puebla
14Bacalar, Quintana Roo34Guadalajara, Jalisco
15Cholula, Puebla [church on hill]35Arco, Los Cabos, Baja California Sur [marine arch]
16Laguna ojo de liebre, Baja California Sur36Tlaxcala, Tlaxcala
17Laguna ojo de liebre, Baja California Sur37Taxco, Guerrero
18Loreto, Baja California Sur38Guerrero Negro, Baja California Sur
19Loreto, Baja California Sur39La Paz, Baja California Sur
20Tequila, Jalisco [railway track at 1:49]40Isla San Francisquito, Baja California Sur

Want to learn more about some of these places? Before resorting to Sr. Google, try our site search function.

Enjoy!

Other video resources on this site:

Mexico’s tallest waterfalls

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Aug 032015
 

As we saw in “How long is Mexico’s coastline?“, geographical “facts” and “records” are often not quite as simple to determine as might appear at first sight.

Take waterfalls for example. Mexico’s “highest” waterfalls are not necessarily the same as Mexico’s “tallest” waterfalls, since height refers to elevation, rather than stature. I’m not sure which is Mexico’s highest waterfall, but assume it is likely to be a small waterfall near the summit of one of Mexico’s many major volcanic peaks.

Mexico’s tallest waterfall, on the other hand, is well-known, or is it? Older sources still list the Cascada de Basaseachic in the Copper Canyon region of northern Mexico as the country’s tallest waterfall. That waterfall is 246 meters (807 feet) tall, according to geographer Robert Schmidt, a calculation subsequent confirmed by measurements made by members of a Mexican climbing expedition.

This short Postandfly video shows the Basaseachic Waterfall from the air:

The Basaseachic Waterfall is normally considered to operate year-round, though very little water flows over it on some occasions during the dry season.

In terms of total drop, however, and if we include waterfalls that are seasonal, the Basaseachic Waterfall is overshadowed by the nearby Cascada de Piedra Bolada (Volada). The Piedra Bolada Waterfall, has a total drop of 453 meters (1486 feet), but flows only during the summer rainy season. It is much less accessible, and its true dimensions were only worked out for the first time by an expedition as recently as 1995 by members of the Speology Group of Ciudad Cuauhtémoc, led by Carlos Lazcano.

This latter sections of this amateur video of the Piedra Bolada Waterfall show some of the amazing scenery in this remote area of Mexico:

Curiously, there is some debate as to whether this waterfall should be called Cascada de Piedra Volada (which would translate as the “Flying Stone Waterfall”) or Cascada de Piedra Bolada (“Round Stone Waterfall”). According to members of the Speology Group of Ciudad Cuauhtémoc, its true name is definitely Piedra Bolada, a name referring to a spherical stone, and used in addition for the local stream and for the nearest human settlement.

So, which is Mexico’s tallest waterfall? Well, it all depends…

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Mexico’s webcams

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Jun 292015
 

There are thousands of webcams operating in Mexico offering armchair geographers the opportunity to see up-to-date images of active volcanoes, megacities, archaeological sties, small towns and tourist resorts.

Many of the major webcams are listed at Webcams de México, which has several great features once you’ve chosen a particular webcam, including access to prior images for any date and time, or the ability to compile an instant time-lapse video covering any period of time.

Links to webcams listed at Webcams de México:

Explore Mexico via its webcams! Enjoy!

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Cueva Cheve, Oaxaca, is one of the world’s deepest cave systems

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Apr 062015
 

Even though most people have never heard of it, Cueva Chevé is one of the deepest cave systems in the world. In 2003, a team led by American speleologist Bill Stone, explored Cueva Chevé, located in the mountainous, pine-clad Sierra de Juárez region of Oaxaca, to a depth of 1484 m (4869 ft). The Cueva Chevé system is thought to have some tunnels (as yet unexplored) that extend even further, to depths beyond 2000 m (6500 ft). By way of comparison, at present the world’s deepest known cave is the Krubera Cave, in the Republic of Georgia, which has a maximum explored depth of 2197 m (7208 ft).

Profile of Cueva Cheve

Profile of Cueva Cheve

How deep might the Cueva Chevé be?

In 1990, colored dye trace experiments showed that there was a hydrological connection between the Chevé Cave and a distant spring (resurgence). This shows that the Cueva Chevé system (including parts not yet explored) has a total vertical fall of 2525 m (8284 ft) over a distance of (north to south) of almost 19 km (11.8 mi).

Because the major risks in exploring any cave system include the possibility of sudden rises in water level, or unexpected water flows through the caves, expeditions to this region are limited to the middle of the dry season (ie February-April). When an expedition gets underway, staging camps are set up underground at intervals, but only in locations believed to be well above flood stage water levels.

Cueva Chevé (see cross section) is shaped like a giant L. The vertical shaft is about 910 m (3000 ft) deep and roughly 3.2 km (2.0 mi) of passages are required to get to the bottom. The remainder is a long, gradually sloping passage that goes on for another 3.2 km and drops roughly 605 m (2000 ft). The cave’s deepest known point is about 11 km (7 mi) from the entrance, where explorers have so far failed to get past a terminal sump.

The air in the cave is relatively warm, with temperatures ranging from 47-52̊ F (8-11̊ C).

Chambers so far explored have been given prosaic names such as “Cuarto de las Canastas” (the Basket Room), “Cuarto del Elefante Negro” (the Black Elephant Room), and “Cañon Fresco” (Fresh Canyon), while named cave formations include the “Taller de Santa Claus” (Santa Claus Workshop). Several parts of the cave system have been found to contain human artifacts, the earliest dating back at least several hundred years.

How to get there

Cueva Chevé is about 140 km (86 mi) north of Oaxaca City via highways 190 and 131.

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Post and Fly Videos of Mexico

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Sep 252014
 

A series of videos made by “Post and Fly Videos” provides an outstanding visual introduction to many of Mexico’s most photogenic sights. Some of the photography is truly stunning.

For a fun introduction, try this 4 minute video (turn your speakers on) which gives a quick tour of many parts of Mexico. (As yet, there are very few Post and Fly Videos of the Yucatan Peninsula, but I’m confident they will remedy this omission before too long!)

A list of the places shown in this 4 minute video is given below (with a few links to relevant Geo-Mexico posts), for those who like to know precisely where particular shots were taken.

Places in the video (in order of appearance):

Marina San José del Cabo, Baja California Sur
El Sidral, San Luis Potosí
Macroplaza Monterrey, Nuevo León
Las Pozas de Xilitla, San Luis Potosí
Tamtoc, San Luis Potosí
Las Estacas, Morelos
Peña del Aire, Hidalgo
El Naranjo, San Luis Potosí
Xochimilco, D.F.
Tamul, San Luis Potosí
Los Cabos, Baja California Sur
Ex Hacienda de Chautla, Puebla
Gran Cenote, Quintana Roo
El Salto, San Luis Potosí
Valle de Bravo, Estado de México
Los Cabos, Baja California Sur
Ex Hacienda de Santa María Regla, Hidalgo
Peña de Bernal, Querétaro
Acopilco, D.F.
Atlixco, Puebla
Kiosco Morisco, D.F.
López Mateos . Baja California Sur
Huasca, Hidalgo
Mantetzulel, San Luis Potosí
Metepec, Estado de México
Todos Santos, Baja California Sur
Tula, Hidalgo
Todos Santos, Baja California
Castillo de la Salud, San Luis Potosí
Holbox, Quintana Roo
Punta Allen, Quintana Roo
Muyil, Quintana Roo
Tepotzotlán, Estado de México
Parque Fundidora, Nuevo León
Santa Fe, D.F.
Balandra, Baja California Sur
Arcos del Sitio, Estado de México
Loreto, Baja California Sur
Tulum, Quintana Roo
Loreto, Baja California Sur
Tulum, Quintana Roo
Xochimilco, D.F.
Todos Santos, Baja California
Aktun Chen, Quintana Roo
Prismas Basálticos, Hidalgo
Marina San José del Cabo, Baja California Sur
Peña del Aire, Hidalgo
López Mateos . Baja California Sur

To see more Post and Fly Videos, explore their website, especially their “Explorando México” section.

Sep 082014
 

In mid-August 2014, this significant fissure (see image) appeared near the city of Hermosillo in northern Mexico, with some press reports opting for headlines such as “The Earth Splits Open”:

fissure-hermosillo-eyewitness-news

While many press reports, especially those in English, tried to link this fissure to faulting and earthquake movements, others were more cautious, saying it was caused by movement of water underground followed by subsidence. Which version is correct? Probably neither is completely correct, since geography often fails to provide a single, definitive reason for things!

The crack is about 1000 meters (two thirds of a mile) long and up to 7 or 8 meters wide and 10 meters deep. While some press reports erroneously claimed that the crack extended across the main, paved, highway #26 between Hermosillo and the coast, its location was actually some distance away from the main highway. The road shown in the image above is a rural, unpaved road about 80 kilometers (50 miles) west of Hermosillo, in an area of farmland, some of which is irrigated.

Could the fissure have been formed by faulting associated with earth tremors or an earthquake? If this was the cause, the fence line, and the line taken by the road would have shifted position and no longer be straight. The image clearly shows that the road has been severed, but provides no evidence that the two sides have shifted position. Indeed, a close-up view confirms that even the existing fence remains in place:

fissure-hermosillo-fence-line

The available evidence therefore rules out faulting (or earth tremors or earthquakes) as the cause of the crack.

Could the fissure have been caused by an underground flow of water followed by subsidence (the collapse of overlying rocks)? This certainly looks more likely though it is hard to imagine significant underground flows of water in an area that is as flat as this. On the other hand, this is (a) an area of newly constructed irrigation ditches and ponds, and (b) it received heavy rainfall a few days before the crack was reported.

In all probability, the fissure began as a deep but very narrow “subsidence fissure” where differences in irrigation (or in water extraction) caused some parts to be much wetter than others. The soil and rock particles in wetter areas would tend to expand, while those in drier areas would tend to contract. Such differences could lead to the formation of small initial fissures.

Once the fissure had been started, localized heavy rains and the resulting overland flow could then result in streams flowing (temporarily) in these initial fissures. The moving stream water would rapidly widen and deepen the fissures into the scale of crack shown in the photos. The initial fissure may have been formed several years before this widening process occurred.

For a more detailed look at the evidence for this fissure’s formation (and its true location), see Debunked: The Earth Splitting Open – Giant Crack in Mexico.

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Where are Mexico’s mangrove swamps?

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Aug 142014
 

The National Commission for the Knowledge and Use of Biodiversity (Comisión Nacional para el Conocimiento y Uso de la Biodiversidad, CONABIO), has identified 81 distinct areas in Mexico that have mangroves with “biological significance and in need of varying degrees of ecological rehabilitation” (see summary map). These regions are distributed as follows:

  • 10 on the northern Pacific Coast
  • 6 on the central Pacific Coast
  • 13 on the southern Pacific Coast
  • 27 on the Gulf of Mexico and
  • 25 on the Yucatán Peninsula.

A national inventory has now been compiled by CONABIO. All areas have been surveyed and preliminary descriptions published including details of their location, size, physical characteristics, socioeconomic conditions, local uses of mangrove, biological details, including vegetation structure, and an assessment of local impacts and risks, management and existing conservation measures.

Map of distribution of mangroves in MexicoThe areas of mangroves have been mapped at a scale of 1:50,000 and satellite photos from 2005-2006 have been used in conjunction with fieldwork to calculate the areas of mangroves. The final map is believed to be more than 90% accurate, a reasonable baseline for future comparisons. CONABIO is planning to resurvey the mangrove areas every 5 years following the same methodology.

According to preliminary comparisons with previous attempts to quantify the extent of mangroves in Mexico (the subject of a future post), the loss of mangroves was greatest in the period 1970-1980, and in 2000-2005, but then diminished in the period 2005-2010.

Between 2005 and 2010, the states where mangrove loss remained high (as a percentage of the total area of mangroves in the state) included Chiapas, Baja Californa Sur and Sonora. However, the states losing the largest areas of mangroves in absolute terms were Quintana Roo, Campeche and Nayarit. Jalisco has the unfortunate distinction of being the state where coastal mangrove loss was highest (in terms of the proportion of its total coastline length bordered by mangroves).

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