By Prof Mehdi Zare

Damavand volcano activities: The hazards and opportunities

July 5, 2021 - 16:34

On the first day of summer 2021, an amateur video went viral on social media showing steam coming out of the summit of Damavand volcano (5671m height, 80km NE of Tehran).

The narration in that video had expressed concern about the possibility and signs of the activation of the Damavand volcano. At the end of that short video, it is stated that "we hope that Damavand volcano will not be activated because it will have dire consequences."  
Of course, a series of organizational and expert comments were published, some of which basically denied that the Damavand volcanic system was active! But it was not clear what is the concept of the activity of a volcanic system like Damavand, volcanic eruptions and related processes directly and indirectly. 

The volcanic material eventually decomposes to form the most fertile soils on earth, and cultivation in these soils has produced abundant food and nurtured civilizations. Civilization has developed in Mazandaran province on the Caspian Sea shorelines and its fertile plains under the direct and indirect influence of the Damavand volcano. 

Internal heat from young volcanic systems is the major producer of geothermal energy. Damavand is the most important geothermal energy potential of Iran. Most of the world's mined metal minerals - such as copper, gold, silver, lead and zinc - are found in magmas found deep in ancient volcanoes such as Damavand.

 Damavand stratovolcano is located 70 km south of the Caspian Sea. Over the last 600,000 years, a young cone has been created next to its old cone; the remains of an old cone seen as a semicircular wall, or part of a super cup north of the new cone in the direction of Gazanak Valley. 

Old Damavand protrudes in Gazanak (or Gazaneh) valley from Haraz Road to the Takht Fereydoun climbing camp and under Yakhar Glacier east of Damavand peak. The sulfur-rich volcanic rocks in yellow, orange and red colors can be seen in Vana next to Haraz Road. These rocks and the resulting soil are full of sulfides that emit the smell of sulfur due to weathering and also produce natural sulfuric acid. 

The outer igneous rocks at the summit are protruding with radial lava flows. Lava spraying in the events of the great explosion of about 280,000 years ago created the older, northern cone. The youngest eruption about 7,300 years ago created new lava flows, especially in the newer cone (south of the Gazanak Valley). Hot springs in Larijan, Baijan, Ab-e-Ask and Gazanak are important symbols of modern activity in the Damavand cone and volcanic system.

In the north of Bayjan, which is higher than 4000 meters in terms of elevation, I have studied the landslides next to Kahroud village, a representative for the large blocks and debris slides that have been moved from about 1 km higher. The major earthquakes of 28 March 1830 AD in Damavand, with an estimated magnitude of 7.0, and 11 April 1935 in Kesout, east-central Alborz with a magnitude of 6.8, and 2 July 1957 in Sangchal, south of Amol with a magnitude of 7.0 have been the triggering cause for some of the major landslides along Damavand Volcano flanks. 

Along Haraz valley and around Damavand peak, a major landslide of Lasem (located between Polour and Ab-e-Ask) due to the eruption of Damavand peak 7,300 years ago and lava flow blocked Haraz valley and created Large Lasem lake. Today the Lasem lake sediments might be visited around Lasem road.

There are large sulfurous stone blocks at the top of Damavand. The diameter of the summit crater is 150m in which there is usually a small frozen lake 40 meters wide. 

The last eruption was set at 7,300 years ago, but some evidence suggests magmatic activity between 2,000 and 3,000 years ago. The volcanoes having at least one eruption in last 10,000 years are considered “active”. Therefore, the Damavand volcano is also active. Additional studies on the physical and chemical properties of hot springs, changes in the depth and volume of magma, and geophysical studies such as magnetometric studies are needed to determine how lava moves, and in particular how the earth's surface rises. Therefore, there is a possibility of re-explosion and re-eruption. 

Of course, new evidence of an imminent eruption has not yet been recorded. Evidence of activities in the Damavand system since 2008 and seismic monitoring and other evidence of Damavand surface dynamics show that lava in the Damavand magmatic chamber may have moved to depths of less than 3000 meters. 

One of the most obvious signs of permanent activity in the Damavand system is the presence of the hot springs of Bayjan and Strabakuh (Star-Abad-Kuh) in the Haraz Valley.

A magnitude 5.1 earthquake in Damavand, 5 km north of Damavand, on the Mosha fault at midnight on May 8, 2020, local time, caused widespread panic among residents of Tehran, parts of Mazandaran and Semnan. The epicenter was reported just 10 kilometers south of Damavand peak, with a depth of 14 kilometers.

 The study of earthquakes of the last decade has shown that the highest seismicity is recorded on the eastern part of the Mosha fault at a depth of 6 to 15 km and has an interesting adaptation to the magmatic chamber of Damavand volcano. Therefore, the interaction on the eastern part of the Mosha fault is related to the activities inside the Damavand magmatic chamber.

On the southern, eastern and western flanks of Damavand Volcano, especially in the east of the summit, the pumice minerals have spread up to 20 km. Explosive eruptions determine the shape of Damavand slopes, and villages on volcanic flanks are built on lava flows. In the event of any future eruption of Damavand, the volcanic ashes will spread on the slopes of the peak to Tehran in the southwest of the peak, and to Baladeh in the Noor Valley and in the center of Central Alborz in the northwest. Some of the recent studies, of course, show that in a large eruption, volcanic material will spread further east of the peak and could spread to the eastern Alborz mountains, and dust and volcanic ash may arrive as far north as Damghan in the east of Semnan Province.

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