word to readers

When we talk to you about Mongolia, this Asian country as big as two and a half times France, wedged between Russia and China, how do you see it?

A country of immense green and open expanses, the steppe, with a few herds, small horses, yurts, nomadic herders... or even a desert and inhospitable mountains.

If you refer to history, a name comes immediately: Genghis Kahn, gathering Mongol tribes and founder of the Mongol Empire.

But you don't think VOLCANOES!

My friend, Pierre Gondolff, who is coming back from there (80 days voyages), told me about the existence of a few volcanoes in this immense country. Let's discover them with his photos.

To the northwest of the capital Oula-Bator, the natural park of Uran Toggo is home to the extinct volcano Uran Uul. This small cinder cone rises 1,686 meters above sea level. From the top of its crater, 500 meters wide and 50 meters deep, you can see a small lake in the hollow of thick forests.

Of an age not determined with certainty, it would be closer to the Khanuy Gol volcanic complex referenced by the GVP, according to Jacques-Marie Bardintzeff, volcanologist accompanying the group.

In the Arkhangai Province, after crossing vast steppes populated by nomadic herders and where yaks and other animals graze, the group reaches the Khorgo – Terkhiin Tsagaan Nuur natural park which is located at an altitude of 2,060 meters above sea level. above sea level.

This natural park is home to two jewels of Mongolia: the lake Terkhiin Tsagaan and the extinct volcano of Khorgo.

The Terkhiin Tsagaan Lake, "the great white lake of the Terkh River", results from the volcanic eruption of Mount Khorgo. The Horgo lava flow was radiocarbon dated to around 4,930 years ago and dammed the Chulutu River, forming Lake Terkhin-Tsagan-Nuur.

Surrounded by craters of other extinct volcanoes, it is 16 km long and 4 to 10 km wide. Its area is 61 km², its average depth 20 meters.

Khorgo, an extinct volcano, rises 2,240 meters above sea level east of Lake Terkhiin Tsagaan. The summit of this volcano is covered in basalt, which was active 8,000 years ago. Its crater is 200 meters in diameter and 70 to 80 meters deep, and is surrounded by small groves of trees. It has been protected since 1965.

Sources:
- Photos by Pierre Gondolff, whom I thank.
- Friendly hello to J.M.Bardintzeff, S. Chermette and P. Thiran, who were on the same trip.
- Global Volcanism Program: Khanuy Gol - link
- Global Volcanism Program: Taryatu-Chulutu - link

After the volcanoes of the Moluccas and those of North Sulawesi, Dominique and Jean-Michel had, on the return to Europe, an appointment with the Sinabung and some friends at Berastagi.

The superb weather exposed the volcanic peaks, and allowed them to take a pleasant hike, to cross a small river to discover a pretty lake, and to make an incursion into a village destroyed during the last eruption. Its inhabitants were moved to Siosar.

Gunung Sinabung is a Pleistocene to Holocene stratovolcano with numerous lava flows on its flanks. Migration of the summit vents along an N-S line gives the summit crater complex an elongated shape.

No confirmed historical eruptions were recorded for over 400 years...before the explosive eruptions of August to September 2010, which produced ash plumes 5 km above the summit.

The PVMBG lowered Sinabung's Alert Level to 2 (on a scale of 1 to 4) on May 11, 2022, noting that data showed stability at the volcano.

On August 9, the Sinabung showed its mood only with a few white fumaroles.

The next day, Dominique and Jean-Michel climbed the Sibayak.

The climb was "simple enough" to discover this giant, dormant since 1881.

The Sibayak, which culminates at 2,181 meters, is a substructure of the Singkut caldera, about 9 km in diameter. Post-caldera cones, the Pratektekan, the Sibayak and the Pintau, its twin, occupy the southern rim of this caldera.

The Sibayak crater is partially filled to the north by the Pintau. A lava flow passed through a breach in the western crater wall from the summit lava dome of Sibayak.

A small lake has occasionally occupied its crater

The active geothermal field, SE of the summit, has abundant solfataras and fumaroles.

Many thanks to Jean-Michel for sharing photos and anecdotes, and my regards to my Indonesian friends.

All my wishes for a pleasant return flight!

Sources:

- Dominique and Jean-Michel ( https://kilauea.info/2022/07/22/)

- PVMBG, Magma Indonesia

- Global Volcanism Program – Sinabung and Singkut

- The words of its silence – Alumni association of Geology ITB (IAGL ITB)

After a flight of a hundred steps, Dominique, Aris and Jean-Michel reach the crater of Mahawu volcano, a still active volcano (listed in the catalog of the Global Volcanism Program). A mini episodic acid lake occupies part of the bottom of the crater.

The lying Mahawu volcano immediately east of Lokon-Empung volcano is the northernmost of a series of young volcanoes along a line SSW-NNE near the caldera margin of the Quaternary Tondano. Mahawu is capped by a 180m wide and 140m deep crater which sometimes contains a small crater lake and has two pyroclastic cones on its N flank.

Its historical activity has been limited to occasional small explosive eruptions recorded since 1789. In 1994 fumaroles, mud pots and small geysers were observed along the shores of a crater lake.

The next day, a road "with hundreds of turns" leads them to the Soputan volcano, one of the most active volcanoes in Sulawesi.

Little visible that day ... only a clearing reveals the summit at 1,785 meters.

The volcano is in level 2 / waspada activity, with a recommendation not to exercise any activity within a radius of 1,500 m from the summit.

The young, largely unvegetated volcano is the only active cone of the Sempu-Soputan volcanic complex, which includes the Soputan, Rindengan and Manimporok caldera (3.5 km ESE).

Kawah Masem, a maar, formed in the western part of the caldera and contains a crater lake; sulfur has been extracted from fumarolic areas of the maar since 1938.

Recent eruptions have originated at both the summit crater and Aeseput, a major NE flank vent that formed in 1906 and was the source of large, intermittent lava flows until 1924.

A small tour on the side of one of these great flows is essential, but it will remain in a foggy atmosphere.

A short day of relaxation after these numerous volcanic ascents... without however giving up volcanism, because on a beach, where a fishing house sits, they discover an area where two types of sand mingle: black sand of volcanic origin, and another clear, almost white, of coral erosion origin.

The icing on the cake: the Tetetana flower garden, on the hill of the same name, where the flowers compete with the very green landscape, with a view of Manado.

Another time for other adventures.

Sources:

- Dominique and Jean-Michel ( https://kilauea.info/2022/07/22/)
- Aris Yanto, guide, graduate in Volcanology University of Kehidupan (contact@idtreks.com - https://www.instagram.com/arisvolcano/)
- Global Volcanism Program – Mahuku and Soputan.

After the difficult ascents of Dukono and Ibu, in the Moluccas archipelago, our friends pass on the island of Siau, in the Indonesian province of North Sulawesi, dominated by the Karangetang, also called "Api Siau".

The activity of the day was weak, characterized by a weak degassing brought down on the summit.

The Karangetang volcano is located in Siau Tagulandang Biaro (Sitaro) regency, North Sulawesi, about 125 km NNE of the most NE point of the island of Sulawesi.

The stratovolcano contains five summit craters along an N-S line. It is one of the most active volcanoes in Indonesia, with over 40 eruptions recorded since 1675 and many additional small eruptions that have not been documented in historical records (Catalogue of Active Volcanoes of the World: Neumann van Padang, 1951). Twentieth-century eruptions have included frequent explosive activity sometimes accompanied by pyroclastic flows and lahars. Lava dome growth has occurred in the summit craters; the collapse of the lava flow fronts produced pyroclastic flows. (Global Volcanism Program)

Then, on Sulawesi itself, the climb to Lokon was made by the bed of the river.

The Tompaluan crater, 150 x 250 m. located in the saddle between Lokon and Empung, is still degassing strongly … sulfur dioxide and large bombs form the environment.

The Lokong-Empung volcanic complex, rising above the Tondano Plain in North Sulawesi, comprises four peaks and one active crater. Lokon, the highest peak, has a flat top with no crater. The morphologically younger Empung cone 2 km to the NE has a 400 m crater. wide and 150 m. depth that last erupted in the 18th century. A ridge extending over 3 km. to the WNW of Lokon includes the Tatawiran and Tetempangan peaks. All eruptions since 1829 have originated from Tompaluan Crater, in the saddle between Lokon and Empung. These eruptions primarily produced weak to moderate ash plumes that occasionally damaged cropland and homes, but lava domes growth and pyroclastic flows also occurred (Global Volcanism Program)

The group then moved on to Lake Linow, a volcanic lake located outside Tomohon, near Manado. Several hydrothermal vents spit hot gas from the edges and depths of the lake.

Continuation of their discoveries in the next episode.

Sources:

- Dominique and Jean-Michel ( https://kilauea.info/2022/07/22/)

- Aris Yanto, guide, graduate in Volcanology University of Kehidupan (contact@idtreks.com - https://www.instagram.com/arisvolcano/)

- Global Volcanism Program - Karangetang and Lokon

- PVMBG

The team left for the base camp of Gunung Ibu around 5am in the morning.

The climb to the volcano, through the jungle, is tough on the knees, with a few scrapes and slips, on terrain that requires attention with every step.

The local porters do not seem handicapped by this environment and climb barefoot.

The night passes on the edge of the crater.

The Gunung Api Ibu was clearly visible on July 28, 2022, until it was covered by fog 0-III. The main crater plume was white and gray, with fine, medium to thick intensity, about 200-800 meters from the summit. The weather is sunny to rainy, the wind is light to moderate in the north, west and northwest.

The seismicity of 28.07 is characterized by:
- 64 eruption earthquakes, with an amplitude of 15-30 mm and an earthquake duration of 20-80 seconds.
- 36 avalanche earthquakes, with an amplitude of 2-11 mm and an earthquake duration of 15-80 seconds.
- 75 emission earthquakes, with an amplitude of 5 to 14 mm and an earthquake duration of 10 to 50 seconds.
- 7 harmonic episodes.
- 46 shallow volcanic earthquakes, with an amplitude of 3 to 9 mm and an earthquake duration of 4 to 12 seconds.
- 1 local tectonic earthquake, with an amplitude of 30 mm, S-P 6 seconds and an earthquake duration of 66 seconds.
- 3 distant tectonic earthquakes

No bulletin from the PVMBG on July 29, but the eruptive activity continued according to the statements and photos of our friends on site.

Their night photos unfortunately did not arrive ... computer problem.

The seismicity of July 30 is characterized by:

- 62 eruption earthquakes, with an amplitude of 15 to 30 mm and an earthquake duration of 20 to 139 seconds.

The PVMBG notes the episode of 30.07 at 7:36 p.m. WIT, accompanied by a thick plume of gray ash at around 3,000 m. above the summit, recorded on a seismograph with an amplitude of 27mm max. for 139 seconds.

In addition, the observatory provides information:
- 18 avalanche earthquakes, with an amplitude of 2 to 10 mm and an earthquake duration of 15 to 60 seconds.
- 52 emission earthquakes, with an amplitude of 5 to 14 mm and an earthquake duration of 10 to 50 seconds.
- 4 harmonic episodes
- 52 shallow volcanic earthquakes, with an amplitude of 3-18 mm and an earthquake duration of 4-10 seconds.

Activity level remains at 2 / waspada, with recommendations:
Communities around Mount Ibu and visitors/tourists should not travel within 2.0 km and the sectoral expansion is 3.5 km towards the crater opening in the northern part of the active crater of Mount Ibu.
In the event of ash rain, people who are active outside the home are advised to use nose, mouth (mask) and eye (goggles) protection.

Sources:

- PVMBG, MAgma Indonesia

- Dominique and Jean-Michel ( https://kilauea.info/2022/07/22/)

- Aris Yanto, guide, graduate in Volcanology University of Kehidupan (contact@idtreks.com - https://www.instagram.com/arisvolcano/)

My friends, Dominique and Jean-Michel (LAVE-Belgium), guided by the Aris Yanto team, just climbed the Dukono last eekend, on Halmahera in the Moluccas archipelago. They make us enjoy their first photos.

The climb was made, through lava fields and rivers descending the slopes, to the base camp, where it rains in the evening.

New night stage, in the wet volcanic ash, following Aris, who must guess the best way to reach the edge of the crater.

A beautiful nocturnal activity, with incandescence at the bottom of the crater, and intense degassing, reward the efforts made.

An expedition postponed two consecutive years because of a small virus, and all the more appreciated.

The Dukono volcano was clearly visible until it was covered in fog on July 25, according to PVMBG.

The eruptive plume observable from the main crater was white and gray, with high intensity, thick about 50-100 meters from the summit, sunny to cloudy weather.

The PVMBG has not reported an eruptive episode since 22.07.2022.

The activity level remains at 2/waspada.

Sources:

- PVMBG, MAgma Indonesia

- Dominique and Jean-Michel  ( https://kilauea.info/2022/07/22/)

- Aris Yanto, guide, graduate in Volcanology University of Kehidupan (contact@idtreks.com  -  https://www.instagram.com/arisvolcano/)

To be continued, ... the Ibu volcano.

Gunung Ibu is clearly visible on July 25, until it is covered by fog 0-III. The main crater plume is white and gray, with a fine, medium to thick intensity, of variable height between 200-2000 meters above the summit. The weather is cloudy to rainy, light to moderate winds from the north, west and northwest.

Seismicity is characterized by :

- 70 eruption earthquakes, with an amplitude of 15-30 mm and the duration of the earthquake 20-170 seconds.
- 20 avalanche earthquakes, with an amplitude of 2-19 mm and an earthquake duration of 15-65 seconds.
- 63 emission earthquakes, with an amplitude of 5 to 14 mm and an earthquake duration of 10 to 50 seconds.
- 11 harmonic episodes, with an amplitude of 2 to 30 mm and an earthquake duration of 65 to 350 seconds.
- 41 shallow volcanic earthquakes, with an amplitude of 3 to 9 mm and an earthquake duration of 4 to 12 seconds.
- 4 deep volcanic earthquakes, with an amplitude of 7-13 mm, S-P 1-3 seconds and an earthquake duration of 7-13 seconds.

Activity is at level 2/waspada, with recommendation for communities around Mount Ibu and visitors/tourists should not travel within 2.0 km and sector expansion is 3.5 km towards the opening of the crater in the northern part of the active crater of Mount Ibu.

Source: PVMBG

Our friend Thierry Sluys invites us to a big overview of the Sinabung realized this Monday, July 15th, 2019.

The Indonesian volcano Sinabung, located north of Sumatra, had its first confirmed Holocene eruption between August 27 and September 18, 2010; ash plumes rose up to 2 km above the summit, and ashes and tephra fell, causing deaths and thousands of evacuations.

He remained calm after the initial eruption until September 15, 2013, when a new eruption began and lasted more than three years.

Its last event dates from May-June 2019.

Many pyroclastic flows and lahars have impacted the population, destroying villages, killing dozens of people and changing the lives of the people and their surroundings for years, forcing long-term evacuations.

The deposits of pyroclastic flows are impressive on the eastern slope of Gunung Sinabung, and on its northern slope, where a whole forest area has been swept.

The ash falls accompanying the regular eruptive plumes were responsible for the abandonment of villages and their partial destruction, the roofs collapsing under the weight of ashes.

Primary and secondary lahars also caused a lot of material damage and ruined lives.

Work has been done for the regulation of rainwater, as here on the North-East side.

Thierry points out the cliff created for the retention, which, although of modest height, delimits the progression of the flows, as well as the presence of ruins of a village (photo below).

Sources:

- Many thanks to Thierry Sluys for his commented sharing of recent images of Sinabung.

Thierry is based in Reunion, where he runs a guest house, with his wife and daughter: "Leu bleu Austral" - contact: www.leubleuaustral.fr/

- Global Volcanism Program - Sinabung