As more days pass since the terrible double earthquake of June 24, more of its aftermath appears, proof of which is the recent discovery in the depths of the Gulf of Paria and the south of the island of Trinidad: the earth literally liquefied, giving rise to an ephemeral, but fascinating mud volcano-island.
In this edition, I bring you this amazing phenomenon with data verified by local geologists and international agencies. Let's begin:
Why was it formed?
This phenomenon is a direct consequence of seismic activity. The energy released by the seismic doublet altered the stress regime in the geological faults connecting Venezuela with Trinidad, reactivating a pre-existing geological fault on the seabed and creating an escape route for fluids and sediments that were trapped and pressurized underground.
The subsoil of this border region accumulates enormous quantities of water, methane gas, and fine sediments (clays) trapped at great depths and under extreme pressure. When powerful seismic waves passed through these layers, they triggered a phenomenon known as sediment liquefaction.
Pressure collapse: Vibrations disrupted the sediment grains, increasing the pressure of water and gases trapped in the earth's pores.
The geological context: the southern anticline
The key to this event lies in the local geology. The southern coast of Trinidad is dominated by the Southern Anticline, a huge fold of rock that runs across the island from east to west.
The escape route: Unable to withstand the pressure, this semi-liquid, dense mixture sought the path of least resistance to the surface through pre-existing faults and fractures in the seabed.
The mud was violently pushed upwards, accumulating on the seabed until it rose above the water level and formed a mud island between 3,6 and 4,5 meters high above sea level.
This system of faults and folds allows water, oil, and gas, compressed at great depths by tectonic plate movement, to rise to the surface. This characteristic makes the area conducive to the formation of mud volcanoes, which do not erupt lava, but rather a mixture of clay, water, gases (mainly methane), and rock fragments.
A 10-million-year journey to the present
Thanks to the analysis of mud samples carried out by the consultancy ResiLog Limited, the Seismic Research Centre of the University of the West Indies and the Institute of Marine Affairs, we now know the inner workings of this structure.
The material is a "time traveler"
Biostratigraphic analysis determined that the expelled mud belongs to the Lengua Formation, meaning it is approximately 10 million years old (Late Miocene). Interestingly, to reach the surface, this mud had to pass through much younger geological layers above it, such as the Cruse and Lower Cruse Formations (between 5 and 8 million years old).
The earthquake fractured the seabed, allowing a mixture of soft clay, rock fragments, and calcite-rich materials to be violently ejected to the surface.
An ephemeral phenomenon
The mud volcano is a temporary island. Wave action is rapidly eroding the structure. In just two days, it lost almost a third of its mass. It will likely disappear in the coming months, a victim of the sea's constant pounding.
Unlike magma and lava volcanoes that solidify into extremely resistant basaltic rock, submarine mud volcanoes are extremely vulnerable to the dynamism of the ocean.
Although the mud exposed to the sun and air began to dry and harden rapidly at its peak, the islet is losing the battle against the sea at an accelerated rate.
It is very likely that, in a matter of weeks or months, the waves will eventually "erase" the island from the surface, leaving it only as an underwater dome.
Regional deformation: It was not the only change; the birth of this mud volcano is just the tip of the iceberg of the drastic geomorphological changes in the area due to the release of elastic energy accumulated in the tectonic faults.
Activation of other volcanoes: The earthquake also increased the activity of existing terrestrial mud volcanoes on the southwest peninsula of Trinidad, showing that the entire underground fluid system of the region reacted in a chain reaction to the great tremor.
This shows that this seismic event not only "shook" our lives and the way we see them, but also nature and even the seabed, which rose up with a large sediment that emerges, just as we will, and unlike them, we will endure through time with a Venezuelan stamp.
