Description

Source: UNIVERSITY OF OXFORD

Disclaimer: Copyright infringement not intended.

Context

Scientists from China, UK & U.S. used advanced seismic tomography & petrological modeling to unravel non-eruptive unrest of Bolivia Uturuncu zombie volcano revealing low eruption risk due to subsurface fluid & gas movement.

Uturuncu Volcano

Feature	Details
Location	Southwestern Bolivia within Andes Mountains.
Volcanic Type	Stratovolcano, dominated by dacitic lava domes & flows.
Elevation	6,008 meters (19,711 feet) above sea level making it tallest mountain in southern part of Bolivia.
Last Eruption	Last erupted approximately 250,000 years ago.
Seismic Activity	Seismically active with frequent earthquake events & ongoing deformation.
Area of Influence	Located at center of a 70 km diameter uplifted region showing active signs of volcanic unrest such as surface deformation & gas emissions.
Magma Reservoir	Sits above Altiplano-Puna Magma Body (APMB), a massive & deep underground reservoir stretching across southern Bolivia, northern Chile & northern Argentina.
Unrest Characteristics	Known as a zombie volcano due to continued but non-eruptive activity such as movement of liquid & gases beneath crater.
Cause of Unrest	The unrest is primarily caused by migration of magma, fluid & gas beneath surface leading to uplift of land at volcano center & subsidence around it.
Risk of Eruption	Low likelihood of imminent eruption despite ongoing seismic activity & deformation.
Scientific Research	Recent studies combined seismic tomography & rock composition analysis to map out volcanic plumbing system which revealed fluid & gas dynamics below surface.
Hydrothermal System	Active hydrothermal system connecting magma body with surface contributing to movement of fluids & gases.
Significance of Study	The study of Uturuncu unrest is crucial for understanding similar zombie volcanoes improving early warning systems for volcanic hazards & refining volcanic hazard modeling.
Tourism & Cultural Significance	The volcano is part of Altiplano region which holds significant cultural & geological importance for local communities & offers scenic vistas for researchers & tourists.

Seismic Tomography

Feature	Details
Definition	A technique used to image interior of Earth using seismic waves generated by earthquakes or artificial sources.
Principle	Seismic waves travel at different speeds through different materials. The variation in speed of these waves helps create a detailed image of subsurface structures.
Types of Seismic Waves	P-waves (primary or pressure waves) faster & can travel through solids, liquids & gases. S-waves (secondary or shear waves) slower & only travel through solids.
Uses in Volcanology	Imaging of magma chambers & reservoirs. Detection of magma movement or pathways. Mapping subsurface structures like faults & fractures that influence volcanic activity.
Application at Uturuncu	Used to identify migration paths of fluids & gases beneath volcano. High-resolution imaging to study volcanic plumbing & shallow crust beneath Uturuncu.
Advantages	Provides 3D imaging of interior. Non-invasive, can be applied without need for drilling. Enables high-precision detection of subsurface dynamics.
Challenges	Requires extensive seismic data collection. Interpretation of results can be complex especially in volcanic regions with multiple subsurface features.

Altiplano-Puna Volcanic Complex (APVC)

Feature	Details
Location	Extends across Altiplano (southern Bolivia), Puna Plateau (northwestern Argentina) & northern Chile.
Size	Covers a vast region of approximately 500,000 square kilometers.
Geological Significance	Home to world largest known magma body beneath Earth's crust known as Altiplano-Puna Magma Body (APMB). Contains large volcanic centers & calderas.
Active Volcanic Centers	Includes Uturuncu, Llullaillaco, Mount Parinacota & Mount Ojos del Salado ( world’s highest active volcano).
Age	The volcanic region has been active for millions of years, with current volcanic activity occurring within last 200,000 years.
Volcanic Activity	Frequent eruptions in past. Ongoing seismic activity, magma upwelling & hydrothermal activity in many of volcanic systems.
Magma Composition	Primarily dacitic & andesitic magmas often associated with explosive eruptions. The presence of large magma bodies beneath these volcanoes is crucial for understanding regional volcanic behavior.
Tectonic Setting	Situated within subduction zone where Nazca Plate is being subducted beneath South American Plate leading to volcanic activity in region.
Environmental Significance	Vital for local ecosystems contributing to mineral deposits. Affects local hydrology, agriculture & surrounding communities.
Human Impact	The region is sparsely populated but volcanic hazards can affect local populations. Affects agriculture with ash fallout & eruption events impacting farming in region.

Hydrothermal System at Uturuncu

Feature	Details
Definition	A hydrothermal system involves circulation of hot fluids such as water & gas through subsurface volcanic structures often resulting in surface manifestations like hot springs & fumaroles.
Components	Magma chamber Supplies heat to hydrothermal system. Water sources Rainwater & underground water that gets heated by underlying magma. Surface features Fumaroles, hot springs, geysers.
Role in Volcanic Systems	Hydrothermal systems transfer heat & gases from deeper layers of Earth to surface influencing volcanic activity, gas emissions & geothermal energy production.
Hydrothermal Activity at Uturuncu	Evidence of active hydrothermal systems connecting surface & Altiplano-Puna Magma Body (APMB) beneath. Movement of gases & liquids contributes to uplift & deformation of land around Uturuncu.
Gas Emissions	The release of gases such as sulfur dioxide, carbon dioxide & water vapor is a common feature of hydrothermal system. These gases can lead to minor volcanic tremors & surface changes.
Deformation Patterns	The sombrero pattern (central uplift & surrounding subsidence) observed on Uturuncu is caused by ongoing migration of geothermal fluids beneath surface.
Risk Assessment	Though Uturuncu remains a zombie volcano hydrothermal system is active leading to ongoing seismic activity. Understanding hydrothermal dynamics helps assess likelihood of future eruptions & associated hazards.
Temperature & Fluid Migration	Geothermal fluids migrate upward contributing to surface deformation & creating underground reservoirs of gas & liquid. The thermal gradients provide valuable data for studying volcanic processes.
Impact on Local Communities	Although there is no immediate eruption risk hydrothermal system activity could influence landscape potentially affecting agriculture, tourism & local infrastructure.

For more such articles, please refer to IAS GYAN

Sources: MSN

PRACTICE QUESTION

Q. The hydrothermal system at Uturuncu has been identified as a key factor in its continued unrest. Examine interaction between magma, fluids & gases in such volcanic systems & their potential impact on local populations.