The movements of our planet are not limited only to the translation around the sun – which gives birth to the seasons – or rotation on its own axis which gives us the phases of day and night.
On a somewhat smaller scale, we find the tectonic plates, which are huge portions of the Earth’s lithosphere in constant motion.
A study published by ESS Open Archive in late 2023 found the surprising situation that is developing on the other side of the world. We are talking specifically about Tibet.
And why are we talking about tectonic plates? Because the main protagonists of this study are these geological pieces located in the Himalayan chain on the Asian continent which, in turn, are part of the gigantic puzzle of the Earth’s lithosphere.
The importance of the interaction between tectonic plates and its consequences
To understand what is happening on the other side of the world, it is necessary to give a “brush stroke” on the important role played by tectonic plates as an essential ingredient in the dynamics of our planet.
The formation of mountains and the occurrence of earthquakes come from the constant interaction of two types of tectonic plates: oceanic and continental.
Tectonic plates are like pieces of a puzzle that make up the earth’s crust. They move on the Earth’s mantle, which, due to the pressures it experiences, can be in the form of a “viscous paste” or in a solid state.
Now imagine the meeting between two tectonic plates, what can happen? Here we have 3 common scenarios:
- one slides over the other;
- they separate;
- or simply, they collide.
In this context, the interaction between the continental tectonic plates, known as the Euroasian and Indian plates, gives rise to the imposing Himalayan range.
Everything is going well so far, but when these 2 tectonic plates have the same density, the conditions become complex, and this is what the study carried out in southern Tibet discovered.
Study results lead to new analyzes of Himalayan seismic activity
In various debates, experts discussed this topic, hypothesizing 2 options. First of all, that the Indian tectonic plate was sinking beneath the Euroasian tectonic plate and, secondly, that the surface part of the Indian tectonic plate was folding as its deepest portion sank into the Earth’s mantle.
The discovery presented by the research team is striking: beneath Tibet, the Indian tectonic plate is fractured in two.
This scenario is completely different from the vertical ruptures caused in tectonic plates like those of Iceland and Africa, because we are talking here about an event in the horizontal direction.
What does that mean ? The Tibetan Plateau is supported by the surface portion of the Indian tectonic plate, while at approximately 33 km depth – specifically in the continental crust – its innermost part sinks into the Earth’s mantle.
One of the most concerning projections, because of what is happening with the Indian tectonic plate, is that it would increase the risk of strong earthquakes in Tibet.
As we can see, there is an extremely important aspect to understand in this situation, because a horizontal break is more complex than a vertical break, what has scientists “on the head” by analyzing this new variable in the seismic activity of Tibet and its medium and long term projections.
Lin Liu, Danian Shi, Simon L Klemperer, et al. Slab tearing and delamination of the Indian lithospheric mantle during flat-slab subduction, southeast Tibet. ESS Open Archive (2023).