: volcán Masaya
) is a caldera
located in Masaya
, 20 km south of the capital Managua
. It is Nicaragua's first and largest national park, and one of 78 protected areas of Nicaragua
. The complex volcano
is composed of a nested set of calderas
, the largest of which is Las Sierras shield volcano
. Within this caldera lies a sub-vent, which is Masaya Volcano sensu stricto
. The vent is a shield
type composing of basaltic lavas
and includes a summit crater
. This hosts Masaya caldera, formed 2,500 years ago by an 8-km³ basaltic ignimbrite
eruption. Inside this caldera a new basaltic complex has grown from eruptions mainly on a semi-circular set of vents that include the Masaya and Nindiri cones. The latter host the pit craters
of Masaya, Santiago, Nindiri and San Pedro. Observations in the walls of the pit craters indicate that there have been several episodes of cone and pit crater formation.
Masaya continually emits large amounts of sulfur dioxide
gas (from the active Santiago crater) and volcanologists study this (amongst other signs) to better understand the behavior of the volcano and also evaluate the impact of acid rain
and the potential for health problems.
The floor of Masaya caldera is mainly covered by poorly vegetated ʻaʻā lava
, indicating resurfacing within the past 1,000 or so years, but only two lava flows have erupted since the sixteenth century. The first, in 1670, was an overflow from the Nindiri crater, which at that time hosted a 1-km-wide lava lake. The other, in 1772, issued from a fissure on the flank of the Masaya cone. Since 1772, lava has appeared at the surface only in the Santiago pit crater (presently active and persistently degassing) and possibly within Nindiri crater in 1852. A lake occupies the far eastern end of the caldera.
Although the recent activity of Masaya has largely been dominated by continuous degassing from an occasionally lava-filled pit crater, a number of discrete explosive events have occurred in the last 50 years.
One such event occurred on November 22, 1999, which was recognised from satellite data. A hot spot appeared on satellite imagery, and there was a possible explosion. On April 23, 2001, the crater exploded and formed a new vent in the bottom of the crater. The explosion sent rocks with diameters up to 60 cm which travelled up to 500 m from the crater. Vehicles in the visitors area were damaged and one person was injured. On October 4, 2003, an eruption cloud was reported at Masaya. The plume rose to a height of ~4.6 km. In 2008, the mountain erupted spewing ash and steam. This volcano is monitored by the Deep Earth Carbon Degassing Project
. Volcanic gas emissions from this volcano are measured by a Multi-Component Gas Analyzer System
, which detects pre-eruptive degassing of rising magmas, improving prediction of volcanic activity
On March 4, 2020, tightrope daredevil, Nik Wallenda
, walked on a steel cable over the caldera.
In 1979, Masaya became Nicaragua's first national park, named Masaya Volcano National Park
(Parque Nacional Volcan Masaya). The park has an area of 54 km² includes two volcanoes and five craters,
as well as a range of elevations between 100 and 630 meters above sea level
. In the park is a lava tube
formed by lava flows; one can find bats
and look inside and observe the glowing lava in the dark crater mouth of the volcano.
An ophiolitic suite is found in the Nicoya
Complex, which is made up of cherts
, tholeiitic pillow lavas
and basaltic agglomerates
. It is intruded by gabbroic
, and dioritic
rocks. The Cretaceous-Tertiary basin is made up of five formations of mainly marine origin. The Rivas and Brito formations
are uplifted to the southeast and are overlain in the northwest by a slightly tilted marine near- shore sequence, the El Fraile formation. This in turn passes north into the undeformed Tamarindo formation, a sequence of shallow marine, lacustrine and terrestrial sediments interspersed with ignimbrites. Northeast of the Nicaraguan Depression, the Coyol and Matagalpa formations, run from Honduras to Costa Rica and still show evidence of some volcanic centres, distinguishable as constructional landforms.
Quaternary volcanic rocks are found mainly in the Nicaraguan Depression
and form two major groups
: the Marrabios and the Sierras formations. The Marrabios Cordillera starts in the northwest with Cosiguina volcano and continues to the southeast with San Cristobal
, La Pelona
. The Hoyo
, Monte Galan
volcanoes are built upon ignimbrite deposits from the nearby Malpaisillo caldera
. South-east of Lake Managua
, the Nejapa alignment, Masaya, Apoyo
which overlie the Sierras ignimbrites, erupted from the Sierras Caldera
surrounding Masaya volcano. Further south in Lake Cocibolca
(or Lake Nicaragua), Zapatera
volcanoes mark the end of Nicaraguan section of the CAVF.
- ^ a b c "Masaya". Global Volcanism Program. Smithsonian Institution. Retrieved 2009-01-22.
- ^ "Real-Time Multi-GAS sensing of volcanic gas composition: experiences from the permanent Etna and Stromboli networks, Geophysical Research Abstracts, Vol. 11, EGU2009-5839"(PDF). Archived (PDF) from the original on 2016-10-01. Retrieved 2016-09-27.
- ^ Haring, Bruce (March 5, 2020). "'Volcano Live!' Sees Nik Wallenda Appease The Gods – And Anger Some Fans". Deadline. Retrieved March 6, 2020.
- ^ a b "Visiting Masaya Volcano National Park". ViaNica. Archived from the original on 2007-09-21. Retrieved 2007-08-03.
- Delmelle, P., Stix, J., Baxter, P.J., Garcia-Alvarez, J. and Barquero, J. (2002). Atmospheric dispersion, environmental effects and potential health hazard associated with the low-altitude gas plume of Masaya volcano, Nicaragua. Bulletin of Volcanology, 10.1007/s00445-002-0221-6
- Rymer, H., van Wyk de Vries, B., Stix, J., and Williams-Jones, G. (1998). Pit crater structure and processes governing persistent activity at Masaya Volcano, Nicaragua. Bulletin of Volcanology, 59, 345–355.
- Williams-Jones, G., Rymer, H., and Rothery, D.A. (2003). Gravity changes and passive degassing at the Masaya caldera complex, Nicaragua. Journal of Volcanology and Geothermal Research, 123(1-2), 137–160.
Last edited on 5 May 2021, at 17:09
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