Smart boulders – can rolling stones gather landslide data?

Featured Image: The Araniko highway stretching towards Kodari – this was once the route to Lhasa. © Michel Royon / Wikimedia Commons

Paper: Development of smart boulders to monitor mass movements via the Internet of Things: a pilot study in Nepal

Authors: Dini, B., Bennett, G. L., Franco, A. M. A., Whitworth, M. R. Z., Cook, K. L., Senn, A., and Reynolds, J. M.

Nepal straddles the Himalayan arc – the collision boundary of the Indian and the Eurasian tectonic plates that crumbled to form the highest mountains in the world, the Himalayas. Its precarious location makes it among the most disaster-prone countries in the world. Its landscape has been shaped, and continues to be shaped by seismic activity – from landslides and earthquakes, to glacial lake outburst floods (GLOFs) where the glacier ice or rock debris at the periphery of a glacial lake break off, resulting in severe floods downslope.

Driving out from Kathmandu city towards Bhaktapur, towards Kodari at the Nepal-China border, the landscape transitions from pagoda-style temples, to settlements, further on to a bleak, boulder-strewn landscape. This is the Araniko highway, built on an old yak track, running alongside the Bhote Koshi river, known to the locals as a difficult, dangerous landscape prone to rockfalls and landslides, especially during the monsoons. Warning signs and steel wire mesh welded to the slopes to mitigate landslides define this stretch, and angular boulders mark where the valleys rise into mountains, and are testimony to the region’s disaster-prone legacy.

The Bhote Koshi river that flows along the Araniko highway is littered with boulders that have worked loose from the valley slopes.
Image credit: Gerd Eichmann (CC BY-SA)

Boulder movement downslope happens due to different kinds of landslides, ranging from abrupt, free-falling rocks to slower flow-like movements. Large boulders are a threat to life and infrastructure, and may amplify landslides when they move downslope or cause floods if they block a river channel. 

In fragile landscapes, understanding when and how boulders move downslope and into river networks could be essential to detecting hazards. A rolling stone or a boulder in this case gathers no moss, they say, but can it gather landslide data? A pilot study by Benedetta Dini et al., in the Bhote Koshi catchment, documents how technology can help detect land movement and find use as early warning systems.

Twenty-three long-range, wireless trackers were drilled into boulders along known landslide or debris flow channels. Movement could be triggered by different events including debris flow, large-scale events or collisions. The sensors were programmed to send routine GPS locations every 24 hours, and an accelerometer would report when the boulder moves. A camera was also set up with a field views across the channels to acquire an image every 30 min. Via image sequences, the location of the sensor-embedded boulders are able to compare to prominent trees to identify and validate the movement data. Based on changes in tilt and displacement of boulders, corresponding to movement within a mass of rocks or downslope respectively, the study found that the sensors could successfully detect both slow and rapid movements. 

In conclusion, despite technical difficulties which could be a focus for future research, smart boulders have good potential as weather-proof, long-term, real-time, cost-effective monitoring tools, not just in Nepal but in other landslide-prone areas across the world.


Smart boulders – can rolling stones gather landslide data? by Devayani Khare is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

Adrift along the Sundarbans mangroves, east India

Mid March 2021, I set out with 2 other wildlife enthusiasts to explore the Sundarbans delta in east India. The 3-hour journey from Kolkata city, on a busy road fringed by industrial towns tapered off at Gadkhali port – civilization’s last ‘land’ frontier before the largest  continuous mangrove stretch in the world. We arrived after dusk, boarded our boat (with a crew of 2 naturalists, 3 boatmen, and a chef!), and were adrift upon dark waterways guided by twinkling village lights. In our haste, we thought little of just how ‘remote’ this wilderness was. 

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Etched in stone: tracing earthquakes through archaeological ruins

The Shore Temple at Mahabalipuram, Tamil Nadu, India

Feature image: Shore Temple at Mahabalipuram, Tamil Nadu, India by Nireekshit, CC BY-SA 3.0

Article: Archaeoseismological potential of the Indian subcontinent.

Authors: Miklós Kázmér, Ashit Baran Roy and Siddharth Prizomwala

India’s ancient monuments whisper more than just stories of past empires and civilizations: they also tell tales of its geological past. Evidence of earthquakes is etched in stone, displacements and warps that can help us identify past seismic events.

India’s documentation of earthquakes is sketchy, pieced together from historical data, monographs, and British records. In 1898, the first seismograph was established in Pune, Maharashtra, but serious instrumental recording only began when the 1967 Koyna Dam earthquake struck.Such a short record is not enough to map out active seismic regions or understand recurring earthquakes, so some scientists are turning to archaeological evidence.

Archaeoseismology studies past earthquakes by analysing damage to archaeological sites. How much damage an earthquake does to a structure depends on how hard or soft the ground beneath is, and damage may be mitigated through preventative building techniques. Earthquakes can result in shifts and tilts in masonry or brickwork, displaced walls, warped floors, missing sections, and sometimes, a complete collapse of the structure. The Earthquake Archaeological Effects (EAE) scale helps categorise the intensity of past earthquakes based on observations of structural damage.

A recent paper by Kazmer et al., looks at earthquake damage to 3 late medieval UNESCO World Heritage sites: Mahabalipuram in Tamil Nadu (7th-8th CE), the Qutub Minar complex in Delhi (12th-19th CE), and Konark near Bhubaneshwar in Odisha state (13th CE). All three sites feature masonry buildings commonly seen in 7th and 12th centuries CE architecture across the Indian subcontinent. The seismic history of the subcontinent is understudied compared to the seismically active Himalayan terrain.

The tilt of masonry wall and floor at the Shore Temple in Mahabalipuram indicates liquefaction, a sudden loss of soil stability that can be caused by a seismic shock.. In the Qutub Minar complex, damage to the minar including masonry blocks at the top of Iltutmish’s tomb with gaps of about 5 cms  are attributed to an earthquake in 1803. At Konark, smaller temples around the Sun Temple display shifted blocks. Other temples are missing a shikhara or deul, the temple spire or tower, which might have been toppled by an earthquake.

Beyond categorising such damage, archaeoseismology can indicate the date or date interval, location, and intensity for both seismically active and less active regions. Comparisons with historical records can offer broader insights into the Indian subcontinent. The volcanic plateau that forms the Indian peninsula has long been considered a ‘stable’ region, yet all 3 sites in this study located on the ‘Indian shield’ indicate otherwise – the region has seen earthquake activity in the past. 

Over the years, monuments have undergone intensive restoration by various rulers, British colonial authorities and the Archaeological Survey of India to preserve them for future generations, but in the process, the evidence of past earthquakes has been erased. Kazmer and co-authors suggest that archaeoseismic studies are conducted before all large-scale restoration projects. That way, we can ensure both the historical and geological legacies are preserved for posterity.


Etched in stone: tracing earthquakes through archaeological ruins by Devayani Khare is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

What lies beneath: tracing human migrations through stone tools, India

A map demonstrating possible migration routes of modern humans

Featured image: Katerina Douka, Michelle O’Reilly, Michael D. Petraglia – On the origin of modern humans: Asian perspectives; Science 08 Dec 2017: Vol. 358, Issue 6368, DOI: 10.1126/science.aai9067 [1], CC BY-SA 4.0 (Wikimedia Commons) with minor edits

Paper: Human occupation of northern India spans the Toba super-eruption ~74,000 years ago

Authors: Chris Clarkson, Clair Harris, Bo Li, Christina M. Neudorf, Richard G. Roberts, Christine Lane, Kasih Norman, Jagannath Pal, Sacha Jones, Ceri Shipton, Jinu Koshy, M.C. Gupta, D.P. Mishra, A.K. Dubey, Nicole Boivin & Michael Petraglia

Modern humans evolved around 200,000 years ago in Africa, and dispersed from there to other parts of the globe. The Out of Africa theory is a well-established model that explains the early dispersal of Homo sapiens or modern humans from Africa, into Asia and Oceania. Among the routes proposed is the Southern Route migration from East Africa to the Near East, across the Red Sea, and around Arabia and the Persian Plateau to India, and then finally with modern humans settling in Asia and Australasia. 

India’s geographic location is a key piece of this puzzle. Mitochondrial DNA of contemporary populations in India indicate that the country was an important stepping stone in the colonisation of Australasia. However, the timeline for the proposed Southern Route migration is still a matter of debate – could dating the arrival and settlement of modern humans in India provide some clues?

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Could corals help study the variability of past Indian monsoons?

Featured image: A coral colony from Maldives, Indian Ocean. Picture credit: Андрей Корман from Pixabay (Public domain)

Paper: Potential of reef building corals to study the past Indian monsoon rainfall variability

Author: Supriyo Chakraborty

Paleooceanographers have often used reef-building corals to study oceanic processes like the El Niño and Southern Oscillation, ocean circulation patterns, air–sea gas exchange, and the Indian Ocean dipole (a.k.a Indian Niño), among others. Yet how exactly do corals provide clues about the physical and chemical conditions of their environments? The answer lies in their skeletons. 

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Where the river flows: India’s catchment crisis

Dandeli river, Karnataka, India

Paper: Insights into riverscape dynamics with hydrological, ecological and social dimensions for water sustenance

Authors: T.V. Ramachandra, S. Vinay, S. Bharath, M.D.Subash Chandran, and Bharath H.Aithal

A catchment or watershed represents an intricate network of streams that coalesce into a river. In ecology, river networks are considered as ecosystems since they facilitate interactions between organisms and their environments. A healthy river ecosystem sustains the biodiversity of fringing forests and aquatic habitats, and enhances the landscape’s resilience to water resource development, droughts and climate change. Rivers provide water for domestic, agricultural and industrial use, and sustain native vegetation which in turn regulates the water cycle, and provides forest-based goods and services.

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Rivers of Memory: India

Paper: Evolution of modern river systems: an assessment of ‘landscape memory’ in Indian river systems

Authors: Vikrant Jain, Sonam, Ajit Singh, Rajiv Sinha, S. K. Tandon

“A river cuts through rock not because of its power, but because of its persistence.”

James N Watkins

In geomorphology, the persistence of rivers is etched into the very landscape – a memory of the forces that once shaped it, and continue to do so, slowly, and inexorably. Landscape memory, as Gary John Brierley once wrote, is the imprint of the past upon contemporary landscapes, which include geologic, climatic, and anthropogenic factors.

The rivers of the Indian subcontinent bear witness to forces that shaped them over millennia – and a recent publication in the Journal of International Geosciences traces the evolution of India’s river systems at different time scales.

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