Sciency Thoughts: Convertgent Plate Margin

Showing posts with label Convertgent Plate Margin. Show all posts

Sunday, 8 October 2023

More than 2000 dead following Magnitude 6.3 Earthquake in northeastern Afghanistan.

The United States Geological Survey recorded a Magnitude 6.3 Earthquake at a depth of 10.0 km, roughly 40 km to the northeast of the city of Herat in northeast Afghanistan, slightly after 11.40 am local time (slightly after 7.10 m GMT) on Saturday 7 October 2023. Six villages are reported to have been more-or-less completely destroyed, with 2053 people currently reported dead, and 9240 injured, with 1329 buildings destroyed or damaged, making the event most deadly Earthquake in Afghanistan for more than two decades. Building collapses are a particular danger in Afghanistan as many buildings are made of mud bricks, which can liquify in Earthquakes, forming a fine dust which asphyxiates people trapped beneath fallen structures. The initial Earthquake has been followed by several large aftershocks, at least three of which have had Magnitudes in excess of 5.0.

Local people searching for survivors in the village of Sarbuland in Herat Province, Afghanistan, following a Magnitude 6.3 Earthquake on 7 October 2023. AFP/Getty Images.

The boundary between the Indian and Eurasian tectonic plates runs close to northern Afghanistan. The Indian Plate is moving northward relative to the Eurasian Plate, causing folding and uplift along this boundary, which has led to the formation of the Hindu Kush Mountains of Afghanistan, the Himalayas and the other mountain ranges of Central Asia., and which makes the nations in this boundary zone prone to Earthquakes.

Plate boundaries and movements beneath southern Pakistan, Iran and the Arabian Sea. University of Southampton.

Thursday, 20 January 2022

Magnitude 5.3 Earthquake off the Athos Peninsula, Greece.

The United States Geological Survey recorded a Magnitude 5.3 Earthquake at a depth of 9.3 km, beneath the Aegean Sea, off the south coast of the Athos Peninsula in northeast Greece, slightly before 1.50 pm local time (slightly before 11.50 am GMT) on Sunday 16 January 2022. No damage or injuries have been reported following this event, but people have reported feeling the event from much of Chalkidiki and Thessaloniki.

The approximate location of the 16 January 2022 Greek Earthquake. USGS.

The Aegean Sea is underlain by the Aegean Sea Plate, a small tectonic plate caught between the African Plate to the south, the Anatolian Plate to the east and the Eurasian Plate to the northwest. The Anatolian Plate is being pushed to the west by the northward movement of the Arabian Plate to the east, pushing the Aegean Plate south and west into collision with the northward moving African Plate. Part of the African Plate is being subducted beneath the Aegean Plate along the Hellenic Trench, which runs to the south of the Greek Islands from Cyprus to Crete then northwest under the Ionian sea parallel to the Peloponnesian Coast. This is not a smooth process, as the plates frequently stick together then break apart once the pressure has built up sufficiently, leading to (fairly frequent) Earthquakes.

Simplified map of the plate movements of the eastern Mediterranean. Univeriteit Utrecht.

Sunday, 22 November 2020

Magnitude 5.3 Earthquake in northern Algeria.

The Centre Seismologique Euro-Méditeranéen recorded a Magnitude 5.3 Earthquake at a depth of 10 km, about 34 km to the northeast of the city of Constantine on the northeast coast of Algeria, slightly before 3.55 am local time (slightly before 2.55 am GMT) on Sunday 22 November 2020. There are no reports of any damage or casualties associated with this event, though it was been felt locally.

The approximate location of the 22 November 2020 Constantine Earthquake. USGS.

Algeria lies on the northernmost part of the African Plate, while southern Europe to the north is part of Eurasia. Africa is pushing into Europe from the south, which causes Earthquakes around the Mediterranean Basin. These are most common in southeast Europe, but those in northwest Africa, while less frequent, are often larger and more deadly.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.