Logo link to homepage

Smithsonian / USGS Weekly Volcanic Activity Report

Weekly Volcanic Activity Map

The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday and averaging 16 reported volcanoes, this is not a comprehensive list of all eruptions this week, but rather a summary of activity that meet criteria discussed in the "Criteria and Disclaimers" section below.

Volcanic activity reported here is preliminary and subject to change. Carefully reviewed, detailed narratives over longer time periods are published as reports of the Bulletin of the Global Volcanism Network available through volcano profile pages.

Smithsonian / USGS Weekly Volcanic Activity Report for the week of 11 July-17 July 2012
Name Country Volcanic Province Eruption Start Date Report Status
Cumbal Colombia Northern Andean Volcanic Arc New
Hierro Spain Canary Volcanic Province New
Pagan United States Mariana Volcanic Arc New
Aira Japan Ryukyu Volcanic Arc 2017 Mar 25 Continuing
Batu Tara Indonesia Sunda Volcanic Arc Continuing
Cleveland United States Aleutian Ridge Volcanic Arc Continuing
Etna Italy Sicily Volcanic Province 2022 Nov 27 Continuing
Fuego Guatemala Central America Volcanic Arc 2002 Jan 4 Continuing
Karymsky Russia Eastern Kamchatka Volcanic Arc 2024 Jun 20 Continuing
Kilauea United States Hawaiian-Emperor Hotspot Volcano Group Continuing
Nevado del Ruiz Colombia Northern Andean Volcanic Arc 2014 Nov 18 Continuing
Popocatepetl Mexico Trans-Mexican Volcanic Belt 2005 Jan 9 Continuing
Sheveluch Russia Eastern Kamchatka Volcanic Arc 1999 Aug 15 Continuing
Soufriere Hills United Kingdom Lesser Antilles Volcanic Arc Continuing
Tungurahua Ecuador Northern Andean Volcanic Arc Continuing
All times are local unless otherwise stated.
Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 20,531 individual reports over 1,239 weeks (average of 17 per week) on 336 different volcanoes.

Search by Date



Use the dropdowns to choose the year and week for archived Weekly Reports.

Use the dropdowns to choose the year and week for archived Weekly Reports.          



Search by Volcano



Agung Cotopaxi Iliamna Little Sitkin Planchon-Peteroa Stromboli
Ahyi Cuicocha Iliwerung Llaima Poas Sulu Range
Aira Cumbal Inielika Lokon-Empung Popocatepetl Sumbing
Akan Dabbahu Ioto Lonquimay Purace Sumisujima
Alaid Davidof Irazu Lopevi Puyehue-Cordon Caulle Sundoro
Alu-Dalafilla Dempo Iya Machin Rabaul Suoh
Ambae Descabezado Grande Izu-Torishima Makushin Raikoke Suretamatai
Ambang Dieng Volcanic Complex Jackson Segment Maly Semyachik Ranakah Suwanosejima
Ambrym Dukono Kaba Manam Raoul Island Taal
Anatahan East Epi Kadovar Manda Hararo Rasshua Tair, Jebel at
Aniakchak Ebeko Kaitoku Seamount Marapi Raung Takawangha
Antillanca Volcanic Complex Ebulobo Kama'ehuakanaloa Maroa Redoubt Talang
Antuco Edgecumbe Kambalny Martin Reventador Tambora
Apoyeque Egon Kanaga Masaya Reykjanes Tanaga
Arenal Ekarma Kanlaon Matthew Island Rincon de la Vieja Tandikat-Singgalang
Asamayama Eldey Karangetang Maule, Laguna del Rinjani Tangkoko-Duasudara
Askja Erebus Karkar Mauna Loa Ritter Island Tangkuban Parahu
Asosan Erta Ale Karthala Mayon Rotorua Tara, Batu
Atka Volcanic Complex Etna Karymsky McDonald Islands Ruang Ta'u
Augustine Etorofu-Yakeyama [Grozny Group] Kasatochi Melebingoy Ruapehu Taupo
Avachinsky Eyjafjallajokull Katla Melimoyu Ruby Telica
Awu Fagradalsfjall Katmai Merapi Ruiz, Nevado del Tenerife
Axial Seamount Fernandina Kavachi Midagahara Sabancaya Tengger Caldera
Azul, Cerro Fogo Kelimutu Misti, El Sakar Three Sisters
Azumayama Fonualei Kelud Miyakejima Salak Tinakula
Bagana Fournaise, Piton de la Kerinci Momotombo San Cristobal Tofua
Balbi Fourpeaked Ketoi Monowai San Miguel Tokachidake
Bamus Fuego Kharimkotan Montagu Island San Vicente Tolbachik
Banda Api Fujisan Kick 'em Jenny Moyorodake [Medvezhia] Sangay Toliman
Bardarbunga Fukutoku-Oka-no-Ba Kie Besi Mutnovsky Sangeang Api Tongariro
Barren Island Galeras Kikai Myojinsho Santa Ana Trident
Batur Galunggung Kilauea Nabro Santa Maria Tungurahua
Bezymianny Gamalama Kirishimayama Negra, Sierra Sao Jorge Turrialba
Bogoslof Gamkonora Kita-Ioto Negro, Cerro Sarigan Ubinas
Brava Gareloi Kizimen Nightingale Island Sarychev Peak Ugashik-Peulik
Bristol Island Gaua Klyuchevskoy Nishinoshima Saunders Ukinrek Maars
Bulusan Gorely Kolokol Group Nisyros Savo Ulawun
Calbuco Great Sitkin Koryaksky Novarupta Semeru Unnamed
Callaqui Grimsvotn Krakatau NW Rota-1 Semisopochnoi Unnamed
Cameroon Guagua Pichincha Krummel-Garbuna-Welcker Nyamulagira Seulawah Agam Veniaminof
Campi Flegrei Guallatiri Krysuvik-Trolladyngja Nyiragongo Sheveluch Villarrica
Campi Flegrei del Mar di Sicilia Guntur Kuchinoerabujima Ofu-Olosega Shishaldin Vulcano
Cayambe Hachijojima Kurikomayama Okataina Simbo West Mata
Chachadake [Tiatia] Hakoneyama Kusatsu-Shiranesan Okmok Sinabung Westdahl
Chaiten Heard Kverkfjoll Ontakesan Sinarka Whakaari/White Island
Chiginagak Hekla La Palma Oraefajokull Siple Witori
Chikurachki Helgrindur Lamington Osorno Sirung Wolf
Chiles-Cerro Negro Hierro Lamongan Pacaya Slamet Wrangell
Chillan, Nevados de Hokkaido-Komagatake Langila Pagan Snaefellsjokull Yakedake
Chirinkotan Home Reef Lanin Palena Volcanic Group Soputan Yasur
Chirpoi Hood Lascar Paluweh Sorikmarapi Yellowstone
Ciremai Huaynaputina Late Panarea Sotara Yufu-Tsurumi
Cleveland Hudson, Cerro Lateiki Papandayan Soufriere Hills Zaozan [Zaosan]
Colima Huila, Nevado del Lengai, Ol Doinyo Pavlof Soufriere St. Vincent Zavodovski
Colo Hunga Tonga-Hunga Ha'apai Leroboleng Pelee South Sarigan Seamount Zhupanovsky
Concepcion Ibu Lewotobi Peuet Sague Spurr Zubair Group
Copahue Ijen Lewotolok Pinatubo St. Helens
 News Feeds and Google Placemarks


Download Smithsonian / USGS Weekly Volcanic Activity Report Network RSS Feed

The RSS (Really Simple Syndication) feed is identical to the Weekly Volcanic Activity Report minus some features including the header information (latitude and longitude and summit elevation), the Geologic Summary, and a link to the volcano's page from the Global Volcanism Program. At the end of each report is a list of the sources used. Each volcano report includes a link from the volcano's name back to the more complete information in the Weekly Volcanic Activity Report on the Smithsonian website. This feature was first made available on 5 March 2008.



Download Smithsonian / USGS Weekly Volcanic Activity Report Network CAP Feed

The CAP (Common Alerting Protocol) feeds are XML files specifically formatted for disaster management. They are similar in content to the RSS feed, but contain no active links.



Download Smithsonian/USGS Weekly Volcanic Activity Report Network Link Download Smithsonian / USGS Weekly Volcanic Activity Report Network Link

A Google Earth network link for the Weekly Volcanic Activity Report can be loaded into the free Google Earth software, and in turn will load placemarks for volcanoes in the current weekly report. Placemark balloons include the volcano name, report date, report text, sources, and links back to the GVP volcano profile page and to the complete Weekly Report for that week. This feature was first made available on 1 April 2009.

 Criteria & Disclaimers

Criteria



The Weekly Volcanic Activity Report does not necessarily include all volcanic activity that occurred on Earth during the week. More than a dozen volcanoes globally have displayed more-or-less continuous eruptive activity for decades or longer, and such routine activity is typically not reported here. Moreover, Earth's sea-floor volcanism is seldom reported even though in theory it represents the single most prolific source of erupted material. The Weekly Volcanic Activity Report summarizes volcanic activity that meets one or more of the following criteria:

- A volcano observatory raises or lowers the alert level at the volcano.
- A volcanic ash advisory has been released by a volcanic ash advisory center (VAAC) stating that an ash cloud has been produced from the volcano.
- A verifiable news report of new activity or a change in activity at the volcano has been issued.
- Observers have reported a significant change in volcanic activity. Such activity can include, but is not restricted to, pyroclastic flows, lahars, lava flows, dome collapse, or increased unrest.

Volcanoes are included in the "New Activity/Unrest" section of the Weekly Volcanic Activity Report if the activity occurs after at least 3 months of quiescence. Once a volcano is included in the "New Activity/Unrest" section, updates will remain in that section unless the activity continues for more than 1 month without escalating, after which time updates will be listed in the "Continuing Activity" section. Volcanoes are also included in the "New Activity/Unrest" section if the volcano is undergoing a period of relatively high unrest, or increasing unrest. This is commonly equal to Alert Level Orange on a scale of Green, Yellow, Orange, Red, where Red is the highest alert. Or alert level 3 on a scale of 1-4 or 1-5.

It is important to note that volcanic activity meeting one or more of these criteria may occur during the week, but may not be included in the Weekly Volcanic Activity Report because we did not receive a report.

Disclaimers



1. The Weekly Volcanic Activity Report is intended to provide timely information about global volcanism on a weekly basis. Consequently, the report is generated rapidly by summarizing volcanic reports from various sources, with little time for fact checking. The accuracy of the Weekly Volcanic Activity Report is dependent upon the quality of the volcanic activity reports we receive. Reports published in the Bulletin of the Global Volcanism Network are cover longer time periods and are more carefully reviewed, although all of the volcanoes discussed in the Weekly Volcanic Activity Report are not necessarily reported in the Bulletin. Because of our emphasis on rapid reporting on the web we have avoided diacritical marks. Reports are updated on the Weekly Volcanic Activity Report web page as they are received, therefore information may be included regarding events that occurred before the current report period.

2. Rapidly developing events lead to coverage that is often fragmentary. Volcanoes, their eruptions, and their plumes and associated atmospheric effects are complex phenomena that may require months to years of data analysis in order to create a comprehensive summary and interpretation of events.

3. Preliminary accounts sometimes contain exaggerations and "false alarms," and accordingly, this report may include some events ultimately found to be erroneous or misleading.

4. Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.

5. USGS Disclaimer Statement for this Website:

Information presented on this website is considered public information and may be distributed or copied. Use of appropriate byline/photo/image credit is requested. We strongly recommend that USGS data be acquired directly from a USGS server and not through other sources that may change the data in some way. While USGS makes every effort to provide accurate and complete information, various data such as names, telephone numbers, etc. may change prior to updating. USGS welcomes suggestions on how to improve our home page and correct errors. USGS provides no warranty, expressed or implied, as to the accuracy, reliability or completeness of furnished data.

Some of the documents on this server may contain live references (or pointers) to information created and maintained by other organizations. Please note that USGS does not control and cannot guarantee the relevance, timeliness, or accuracy of these outside materials.

For site security purposes and to ensure that this service remains available to all users, this government computer system employs software programs to monitor network traffic to identify unauthorized attempts to upload or change information, or otherwise cause damage. Unauthorized attempts to upload information or change information on this website are strictly prohibited and may be punishable under the Computer Fraud and Abuse Act of 1986 and the National Information Infrastructure Protection Act. Information may also be used for authorized law enforcement investigations. (Last modified September 21, 1999.)

U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA
URL: https://volcano.si.edu/reports_weekly.cfm

 Acronyms and Abbreviations

a.s.l. - above sea level

AVO - Alaska Volcano Observatory

AVHRR - Advanced Very High Resolution Radiometer

CENAPRED - Centro Nacionale de Prevencion de Desastres (México)

CONRED - Coordinadora Nacional para la Reducción de Desastres

COSPEC - Correlation Spectrometer

CVGHM (formerly VSI) - Center of Volcanology and Geological Hazard Mitigation

CVO - Cascades Volcano Observatory (USGS)

GMS - Geostationary Meteorological Satellite

GOES - Geostationary Operational Environmental Satellite

GVO - Goma Volcano Observatory

GVP - Global Volcanism Program (Smithsonian Institution)

HVO - Hawaiian Volcano Observatory (USGS)

ICE - Instituto Costarricense de Electricidad (Costa Rica)

IG - Instituto Geofísico (Ecuador)

IGNS - Institute of Geological and Nuclear Sciences (New Zealand) - now GNS Science

INETER - Instituto Nicaragüense de Estudios Territoriales (Nicaragua)

INGEMMET - Instituto Geológical Minero y Metalúrgico (Peru)

INGEOMINAS - Instituto Colombiano de Geología y Minería (Colombia)

INGV-CT - Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Catania (Italy)

INSIVUMEH - Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hidrologia (Guatemala)

IRD - Institut de Recherche pour le Développement (France)

JMA - Japanese Meteorological Agency

KEMSD - Kamchatkan Experimental and Methodical Seismilogical Department

KVERT - Kamchatkan Volcanic Eruption Response Team

M - magnitude

METEOSAT - Meteorological Satellite

MEVO - Mount Erebus Volcano Observatory

MODIS - Moderate Resolution Imaging Spectroradiometer

MVO - Montserrat Volcano Observatory

MWO - Meteorological Watch Office

NEIC - National Earthquake Information Center

NIED - National Research Institute for Earth Science and Disaster Prevention (Japan)

NOAA - National Oceanic and Atmospheric Administration

NOTAM - Notice to Airmen

OVDAS - Observatorio Volcanologico de los Andes del Sur (Chile)

OFDA - Office of US Foreign Disaster Assistance

ONEMI - Oficina Nacional de Emergencia - Ministerio del Interior (Chile)

OVPDLF - Observatoire Volcanologique du Piton de la Fournaise (France)

OVSICORI-UNA - Observatorio Vulcanologico y Sismologico de Costa Rica, Universidad Nacional (Costa Rica)

PHIVOLCS - Philippine Institute of Volcanology and Seismology (Philippines)

RSAM - Real-time Seismic Amplitude Measurement

RVO - Rabaul Volcano Observatory

SERNAGEOMIN - Servicio Nacional de Geologia y Mineria (Chile)

SIGMET - Significant Meteorological Information

SNET - Servicio Nacional de Estudios Territoriales (El Salvador)

SVERT - Sakhalin Volcanic Eruption Response Team (Russia)

USAID - US Agency for International Development

USGS - United States Geological Survey

UTC - Coordinated Universal Time

VAAC - Volcanic Ash Advisory Center

VAFTAD - Volcanic Ash Forecast Transport And Dispersion

VDAP - Volcano Disaster Assistance Program (USGS)

VHP - Volcano Hazards Program (USGS)

VRC - Volcano Research Center (Japan)

Report for Cumbal
According to INGEOMINAS, a 10 July report from the Observatorio de Pasto noted that during recent months seismic swarms at Cumbal had been detected. Steam plumes from fumarolic fields were common. Nearby residents reported increases in gas emissions and seismicity, as well as possible noises. The Alert Level was increased to III (Yellow; "changes in the behavior of volcanic activity").
Source: Servicio Geológico Colombiano (SGC)
Report for Hierro
Instituto Geográfico Nacional (IGN) reported that during 11-17 July both seismic activity and deformation at El Hierro decreased. There were 87 seismic events located, most of them offshore SW of El Hierro Island at about 20 km depth. Only six earthquakes were M 2.7 or higher, and the maximum magnitude recorded was 3.4, corresponding to two events: 14 July at 1952 and 17 July at 0746. The deformation rate decreased, with maximum values of less than 1 cm in the horizontal components.
Source: Instituto Geográfico Nacional (IGN)
Report for Pagan
According to the USGS, a minor, low-altitude ash cloud from Pagan was reported by the Washington VAAC on 10 July and confirmed by the Alaska Volcano Observatory (AVO). The VAAC noted that the plume drifted almost 50 km NW at an altitude of 1.5 km (5,000 ft) a.s.l. Local observers indicated localized ashfall on or near the island. The Volcano Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.
Sources: Emergency Management Office of the Commonwealth of the Mariana Islands and United States Geological Survey Volcano Hazards Program, Washington Volcanic Ash Advisory Center (VAAC)
Report for Aira
JMA reported that explosions from Sakura-jima's Showa Crater on 13, 15, and 17 July ejected tephra as far as 1,300 m from the crater. Based on information from JMA, the Tokyo VAAC reported that an explosion on 10 July produced an ash plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted N. Explosions during 16-17 July produced plumes that rose to an altitude of 1.8-3 km (6,000-10,000 ft) a.s.l. and drifted NE, N, NW, and W.
Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Japan Meteorological Agency (JMA)
Report for Batu Tara
Based on analyses of satellite imagery, the Darwin Volcanic Ash Advisory Centre (VAAC) reported that during 13-15 July ash plumes from Batu Tara rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 55-110 km NW and W.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Report for Cleveland
AVO reported that on 11 July a low-altitude ash cloud from Cleveland was detected in satellite imagery. During 12-15 July cloud cover prevented views of the volcano. Elevated surface temperatures were detected in images on 15 July. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Etna
Sezione di Catania - Osservatorio Etneo reported that on the evening of 2 July weak incandescence began to illuminate a gas plume rising from Bocca Nuova, marking the resumption of eruptive activity in this crater nearly one year after a short period of Strombolian and effusive activity. Observatory staff visited the crater the next day and observed Strombolian activity from a single vent, a few meters in diameter, at the base of the SE crater wall. Incandescent bombs and scoria ejected by the explosions fell back around the vent.

During the following days, the activity within Bocca Nuova continued with minor fluctuations; on 4 July, a few bombs fell outside the E crater rim, and on 8 July a small lava flow was observed on the flank of the pyroclastic cone growing around the active vent. Similar activity was also observed on 11 and 13 July. On 16 July, the amplitude of the volcanic tremor recorded by the summit seismic network showed a consistent increase, which was accompanied by an intensification of the activity within Bocca Nuova. During the night of 16-17 July, continuous, bright glow from the crater was visible from populated areas around the volcano.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Fuego
INSIVUMEH reported that on 10 July lahars traveled SE down Fuego's Las Lajas and El Jute drainages carrying blocks 1-1.5 m in diameter. The lahar in Las Lajas was hot and had a sulfur odor. During 10-12 July explosions from Fuego produced ash plumes that rose 150-800 m above the crater and drifted W. On 11 July ashfall was reported in Sangre de Cristo (8 km WSW) and surrounding areas. Tephra avalanches descended the Ceniza (SSW) drainage. During 16-17 July explosions generated ash plumes that rose 200-600 m above the crater and drifted 10 km S and SW. Incandescence emanated from the crater and avalanches descended the Taniluyá (SW) and Ceniza (SSW) drainages.

In a special bulletin on 17 July, INSIVUMEH reported that seismic patterns indicated the beginning of a new phase of activity; avalanches on the S and SW flanks were constantly active, and a new lava flow emerged on the SW flank that traveled 200 m and produced blocks that rolled SW down the Taniluya drainage.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Karymsky
KVERT reported that moderate seismic activity from Karymsky continued to be detected during 6-16 July, and indicated that possible ash plumes rose to an altitude of 2.5 km (8,200 ft) a.s.l. Satellite imagery showed a weak thermal anomaly on the volcano on 12 and 14 July. The Aviation Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Report for Kilauea
During 11-17 July HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Measurements indicated that the gas plume from the vent continued to deposit variable amounts of spatter and Pele's hair onto nearby areas. The lava pond in a small pit on the E edge of the Pu'u 'O'o crater floor was 7-8 m below the rim on 12 July. The pond and two vents along the S edge of the floor were visible with the web cameras. A vent on the W part of the crater was also briefly incandescent. Lava flows were active on the pali and the coastal plain; the active lava-flow front was about 1.3 km from the ocean.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Report for Nevado del Ruiz
According to INGEOMINAS, the Observatorio Vulcanológico and Sismológico de Manizales reported that on 11 July seismicity at Nevado del Ruiz decreased, however the data continued to indicate gas and ash emissions during 11-17 July. Satellite imagery and ground-based observations showed sulfur dioxide emissions. On 11 July ashfall was reported in Pereira (40 km WSW). The Alert Level remained at II (Orange; "eruption likely within days or weeks").
Source: Servicio Geológico Colombiano (SGC)
Report for Popocatepetl
CENAPRED reported that during 10-17 July seismicity at Popocatépetl indicated continuing gas-and-ash emissions; cloud cover prevented observations during most of this period. Incandescence from the crater was periodically observed and sometimes increased with accompanying emissions. On 11 July a gas-and-steam plume rose 1.5 km above the crater and drifted WSW. On 16 July an ash plume rose 1.2 km and drifted SE. A few minutes later a gas-and-steam plume rose 1.5 km. The Alert Level remained at Yellow, Phase Three.
Source: Centro Nacional de Prevencion de Desastres (CENAPRED)
Report for Sheveluch
KVERT reported that during 6-13 July explosive activity at Shiveluch continued and seismic data indicated that possible ash plumes rose to an altitude of 4.5 km (14,700 ft) a.s.l. Observers noted gas-and-steam activity on 11 and 16 July; weather conditions prevented observations of the volcano on the other days. Satellite imagery showed a thermal anomaly on the lava dome during 7-12 and 14-16 July. The Aviation Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Report for Soufriere Hills
MVO reported that during 6-13 July activity at the Soufrière Hills lava dome was at a low level. Mild roaring was heard in nearby locations. A few small pyroclastic flows occurred on the E side of the lava dome, at the head of the Tar River Valley, and traveled less than 1 km. The Hazard Level remained at 2 (on a scale of 1-5).
Source: Montserrat Volcano Observatory (MVO)
Report for Tungurahua
IG reported that during 10-12 July explosions from Tungurahua were detected by the seismic network. On 11 July a gas-and-ash plume rose 1 km above the crater and drifted W. Residents reported "cannon shot" sounds, along with sounds resembling blocks rolling down the flanks. Slight ashfall was reported in Bilbao (8 km W). On 12 July gas-and-steam plumes rose 0.3-1 km high and an ash plume rose 1.5 km high. Cloud cover often prevented observations of the volcano during 13-16 July; clear views on the morning of 15 July showed no activity at the crater. A small explosion was detected on 14 July and an explosion on 17 July generated a steam plume with low ash content.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)