Global Volcanism Program

The Global Volcanism Program has no activity reports available for Atacazo.

The Global Volcanism Program has no Weekly Reports available for Atacazo.

The Global Volcanism Program has no Bulletin Reports available for Atacazo.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Cones

Feature Name

Feature Type

Elevation

Latitude

Longitude

Caracha, La

Stratovolcano

Domes

Feature Name

Feature Type

Elevation

Latitude

Longitude

Arenal I

Dome

0° 22' 0" S

78° 41' 0" W

Arenal II

Dome

4280 m

Cocha I, La

Dome

3798 m

Cocha II, La

Dome

3798 m

Cuscungo

Dome

Gallo Cantano

Dome

Ninahuilca
Minasguilca Chico

Dome

3834 m

0° 22' 16" S

78° 38' 20" W

Ninahuilca Chico I

Dome

Ninahuilca Chico II

Dome

Omoturco

Dome

3566 m

0° 24' 0" S

78° 36' 0" W

Viudita, La

Dome

3724 m

0° 25' 0" S

78° 37' 0" W

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude

352021

320 BCE

4,463 m / 14,642 ft

0.353°S
78.617°W

Morphology

Volcano Landform
Composite

Volcano Types
Stratovolcano
Caldera
Lava dome(s)

Rock Types

Major
Andesite / Basaltic Andesite
Dacite

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km

449
212,988
1,837,303
3,769,593

Geological Summary

Atacazo, located about 25 km SW of Quito, consists of a large Pleistocene andesitic stratovolcanoes truncated by a late-Pleistocene to Holocene caldera. Growth of the La Carcacha edifice was followed by construction of Atacazo, a stratovolcano with flank lava domes. The 6-km-wide caldera, which is breached to the SW, is partially filled by three dacitic Holocene lava-dome complexes. Two andesitic lava domes are also found on the SE flank. Several plinian eruptions have occurred at the Atacazo-Ninahuilca complex during the Holocene, accompanied by growth of lava domes. The latest dated eruption took place about 2300 years ago, forming the Ninahuilca Chico lava domes within the summit caldera. Dome formation was accompanied by Plinian explosive eruptions and pyroclastic flows that traveled 35 km down valleys to the west.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Barragan R, Geist D, Hall M, Larson P, Kurz M, 1998. Subduction controls on the compositions of lavas from the Ecuadorian Andes. Earth Planet Sci Lett, 154: 153-166.

Hall M L, 1977. El Volcanismo en El Ecuador. Quito: Biblioteca Ecuador, 120 p.

Hall M L, Wood C A, 1985. Volcano-tectonic segmentation of the northern Andes. Geology 13:203-207.

Hidalgo S, Monzier M, ALmeida E, Chazot G, Eissen J-P, van der Plicht J, Hall M L, 2008. Late Pleistocene and Holocene activity of the Atacazo-Ninahuilca volcanic complex (Ecuador). J. Volcanol. Geotherm. Res., 176: 16-26.

Eruptive History

There is data available for 4 confirmed Holocene eruptive periods.

0320 BCE ± 16 years Confirmed Eruption VEI: 5

Episode 1 | Eruption

Ninahuilca Chico II dome, N6 tephra

0320 BCE ± 16 years - Unknown

Evidence from Isotopic: 14C (uncalibrated)

List of 6 Events for Episode 1 at Ninahuilca Chico II dome, N6 tephra

Start Date	End Date	Event Type
- - - -	- - - -	Explosion
- - - -	- - - -	Pyroclastic flow
- - - -	- - - -	Lava dome
- - - -	- - - -	Ash
- - - -	- - - -	Pumice
0320 BCE ± 16 years	- - - -	VEI (Explosivity Index)

2490 BCE ± 40 years Confirmed Eruption VEI: 5

Episode 1 | Eruption

Ninahuilca Chico I dome , N5 tephra

2490 BCE ± 40 years - Unknown

Evidence from Isotopic: 14C (uncalibrated)

List of 6 Events for Episode 1 at Ninahuilca Chico I dome , N5 tephra

Start Date	End Date	Event Type
- - - -	- - - -	Explosion
- - - -	- - - -	Pyroclastic flow
- - - -	- - - -	Lava dome
- - - -	- - - -	Ash
- - - -	- - - -	Pumice
2490 BCE ± 40 years	- - - -	VEI (Explosivity Index)

3490 BCE ± 100 years Confirmed Eruption VEI: 4

Episode 1 | Eruption

Arenal II dome, N4 tephra

3490 BCE ± 100 years - Unknown

Evidence from Isotopic: 14C (uncalibrated)

List of 6 Events for Episode 1 at Arenal II dome, N4 tephra

Start Date	End Date	Event Type
- - - -	- - - -	Explosion
- - - -	- - - -	Pyroclastic flow
- - - -	- - - -	Lava dome
- - - -	- - - -	Ash
- - - -	- - - -	Pumice
3490 BCE ± 100 years	- - - -	VEI (Explosivity Index)

6910 BCE (in or before) Confirmed Eruption VEI: 4

Episode 1 | Eruption

La Cocha II dome, N3 tephra

6910 BCE (in or before) - Unknown

Evidence from Isotopic: 14C (uncalibrated)

List of 5 Events for Episode 1 at La Cocha II dome, N3 tephra

Start Date	End Date	Event Type
- - - -	- - - -	Explosion
- - - -	- - - -	Lava dome
- - - -	- - - -	Ash
- - - -	- - - -	Pumice
6910 BCE (in or before)	- - - -	VEI (Explosivity Index)

Deformation History

There is no Deformation History data available for Atacazo.

Emission History

There is no Emissions History data available for Atacazo.

Photo Gallery

Atacazo stratovolcano, located 20 km south of Quito, is seen here from the west along the road to Guayaquil. The volcano contains a summit caldera that is partially filled by lava domes of Holocene age. Lava domes are also found on the SE flank. The only dated Holocene eruption took place about 2400 years ago, forming the Ninahuilca lava domes, the peaks below the center horizon.

Photo by John Ewert, 1992 (U.S. Geological Survey).

The Ninahuilca lava domes, which form the twin forested peaks below the right-center horizon, were created during an eruption about 2400 years ago. Growth of the lava domes within the summit caldera of Atacazo volcano was accompanied by plinian explosive eruptions and pyroclastic flows that traveled 35 km down valleys to the west.

Photo by John Ewert, 1992 (U.S. Geological Survey).

GVP Map Holdings

Maps are not currently available due to technical issues.

Smithsonian Sample Collections Database

There are no samples for Atacazo in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

External Sites

Copernicus Browser

The Copernicus Browser replaced the Sentinel Hub Playground browser in 2023, to provide access to Earth observation archives from the Copernicus Data Space Ecosystem, the main distribution platform for data from the EU Copernicus missions.

MIROVA

Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.

MODVOLC Thermal Alerts

Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.

WOVOdat
   Single Volcano View
   Temporal Evolution of Unrest
   Side by Side Volcanoes

WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.

GVMID Data on Volcano Monitoring Infrastructure The Global Volcano Monitoring Infrastructure Database GVMID, is aimed at documenting and improving capabilities of volcano monitoring from the ground and space. GVMID should provide a snapshot and baseline view of the techniques and instrumentation that are in place at various volcanoes, which can be use by volcano observatories as reference to setup new monitoring system or improving networks at a specific volcano. These data will allow identification of what monitoring gaps exist, which can be then targeted by remote sensing infrastructure and future instrument deployments.

Volcanic Hazard Maps

The IAVCEI Commission on Volcanic Hazards and Risk has a Volcanic Hazard Maps database designed to serve as a resource for hazard mappers (or other interested parties) to explore how common issues in hazard map development have been addressed at different volcanoes, in different countries, for different hazards, and for different intended audiences. In addition to the comprehensive, searchable Volcanic Hazard Maps Database, this website contains information about diversity of volcanic hazard maps, illustrated using examples from the database. This site is for educational purposes related to volcanic hazard maps. Hazard maps found on this website should not be used for emergency purposes. For the most recent, official hazard map for a particular volcano, please seek out the proper institutional authorities on the matter.

IRIS seismic stations/networks

Incorporated Research Institutions for Seismology (IRIS) Data Services map showing the location of seismic stations from all available networks (permanent or temporary) within a radius of 0.18° (about 20 km at mid-latitudes) from the given location of Atacazo. Users can customize a variety of filters and options in the left panel. Note that if there are no stations are known the map will default to show the entire world with a "No data matched request" error notice.

UNAVCO GPS/GNSS stations

Geodetic Data Services map from UNAVCO showing the location of GPS/GNSS stations from all available networks (permanent or temporary) within a radius of 20 km from the given location of Atacazo. Users can customize the data search based on station or network names, location, and time window. Requires Adobe Flash Player.

DECADE Data

The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the Mapping Gas Emissions (MaGa) Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO₂ to the atmosphere, but installing CO₂ monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere.

Large Eruptions of Atacazo

Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).

EarthChem

EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).