London Daily

Focus on the big picture.
Sunday, Oct 05, 2025

What is an aftershock - and why are mass landslides now likely after the earthquake that hit Turkey and Syria?

What is an aftershock - and why are mass landslides now likely after the earthquake that hit Turkey and Syria?

The earthquake that caused such huge devastation in Turkey and Syria occurred along the East Anatolian Fault zone and was followed by dozens of aftershocks.

Two powerful earthquakes and dozens of aftershocks have wrought incalculable destruction on parts of Turkey and Syria, with much of the devastation hitting communities already vulnerable following a decade of war.

It is feared the death toll could rise to more than 20,000.

The initial 7.8 magnitude quake was followed by a 6.7 magnitude aftershock just 11 minutes later.

Another quake - almost as strong as the first, at 7.5 magnitude - hit the area within hours on Monday.



What causes earthquakes?


An earthquake is caused by what's known as a "sudden slip" on a fault line.

The Earth's tectonic plates are always moving, but they can get stuck at their edges due to friction, the United States Geological Survey (USGS) says.

It's when this stress at the edge overcomes the friction that an earthquake occurs, releasing energy in waves that travel through the Earth's crust and cause the shakes that we feel on the surface.

Yesterday's quake struck along the East Anatolian Fault zone, which runs from eastern to south-central Turkey.

Alex Hatem, a USGS research geologist, said in this case, "one plate moved west while the other moved east".

A satellite map of areas impacted by the Turkey-Syria earthquake. Pic: United Nations Satellite Centre


The Turkey-Syria disaster is thought to be a "strike-slip" quake, which occurs when two tectonic plates slide past each other horizontally.

What's the difference between an earthquake and an aftershock?


Aftershocks are a sequence of quakes that happen after the larger "mainshock" on a fault.

They tend to occur near the fault where the mainshock occurred and are part of the "readjustment process" after the main slip on the fault, the scientists at USGS say.

They become less frequent as time passes following the initial shock, but can continue for days, weeks, months, or even years.

When an earthquake hit the East Anatolian area in 1822, aftershocks continued throughout the following year.

The strongest aftershock after yesterday's quake was recorded as a 7.5 magnitude quake.

That's what made this such a rare and unusual disaster.

The last time there were any tremors of similar strength in the region was in 1872.

Several fault lines run through Turkey and Syria


The major aftershock was probably caused by the initial quake destabilising an adjacent fault that had also accumulated geological stresses over the years.

No wonder then that Stephen Hicks, a seismologist at University College London, told Sky News on Monday that what Turkey and Syria have experienced is "the worst kind of earthquake".

Why are mass landslides likely following the earthquake?


Professor Bruce Malamud, an expert in natural and environmental Hazards at King's College London, warns that "hundreds if not thousands" of landslides could now follow the devastating earthquake.

It means that thousands of people affected by the quake could face fresh danger.

Strong earthquake ground shaking increases the likelihood of landslides in certain areas.

If the ground is saturated with water, particularly following heavy rainfall, the shaking will result in more landslides than normal.

e said: "As a result of the Turkey earthquake, the hazard relief agencies and managers will also be conscious of other natural hazards and multi-hazard cascades.

"The seismic activity will likely trigger hundreds if not thousands of landslides in the hours to days after the earthquake and subsequent aftershocks."

Those organising the large-scale evacuations of people will need to be conscious that they are not transferred to an at-risk area.

Newsletter

Related Articles

0:00
0:00
Close
Trump Stands Firm in Shutdown Showdown and Declares War on Drug Cartels — Turning Crisis into Opportunity
Surge of U.S. Billionaires Transforms London’s Peninsula Apartments into Ultra-Luxury Stronghold
Pro Europe and Anti-War Babiš Poised to Return to Power After Czech Parliamentary Vote
Jeff Bezos Calls AI Surge a ‘Good’ Bubble, Urges Focus on Lasting Innovation
Japan’s Ruling Party Chooses Sanae Takaichi, Clearing Path to First Female Prime Minister
Sean ‘Diddy’ Combs Sentenced to Fifty Months in Prison Following Prostitution Conviction
Taylor Swift’s ‘Showgirl’ Launch Extends Billion-Dollar Empire
Trump Administration Launches “TrumpRx” Plan to Enable Direct Drug Sales at Deep Discounts
Trump Announces Intention to Impose 100 Percent Tariff on Foreign-Made Films
Altman Says GPT-5 Already Outpaces Him, Warns AI Could Automate 40% of Work
Singapore and Hong Kong Vie to Dominate Asia’s Rising Gold Trade
Trump Organization Teams with Saudi Developer on $1 Billion Trump Plaza in Jeddah
Manhattan Sees Surge in Office-to-Housing Conversions, Highest Since 2008
Switzerland and U.S. Issue Joint Assurance Against Currency Manipulation
Electronic Arts to Be Taken Private in Historic $55 Billion Buyout
Thomas Jacob Sanford Named as Suspect in Deadly Michigan Church Shooting and Arson
Russian Research Vessel 'Yantar' Tracked Mapping Europe’s Subsea Cables, Raising Security Alarms
New York Man Arrested After On-Air Confession to 2017 Parents’ Murders
U.S. Defense Chief Orders Sudden Summit of Hundreds of Generals and Admirals
Global Cruise Industry Posts Dramatic Comeback with 34.6 Million Passengers in 2024
Trump Claims FBI Planted 274 Agents at Capitol Riot, Citing Unverified Reports
India: Internet Suspended in Bareilly Amid Communal Clashes Between Muslims and Hindus
Supreme Court Extends Freeze on Nearly $5 Billion in U.S. Foreign Aid at Trump’s Request
Archaeologists Recover Statues and Temples from 2,000-Year-Old Sunken City off Alexandria
China Deploys 2,000 Workers to Spain to Build Major EV Battery Factory, Raising European Dependence
Speed Takes Over: How Drive-Through Coffee Chains Are Rewriting U.S. Coffee Culture
U.S. Demands Brussels Scrutinize Digital Rules to Prevent Bias Against American Tech
Ringo Starr Champions Enduring Beatles Legacy While Debuting Las Vegas Art Show
Private Equity’s Fundraising Surge Triggers Concern of European Market Shake-Out
Colombian President Petro Vows to Mobilize Volunteers for Gaza and Joins List of Fighters
FBI Removes Agents Who Kneeled at 2020 Protest, Citing Breach of Professional Conduct
Trump Alleges ‘Triple Sabotage’ at United Nations After Escalator and Teleprompter Failures
Shock in France: 5 Years in Prison for Former President Nicolas Sarkozy
Tokyo’s Jimbōchō Named World’s Coolest Neighbourhood for 2025
European Officials Fear Trump May Shift Blame for Ukraine War onto EU
BNP Paribas Abandons Ban on 'Controversial Weapons' Financing Amid Europe’s Defence Push
Typhoon Ragasa Leaves Trail of Destruction Across East Asia Before Making Landfall in China
The Personality Rights Challenge in India’s AI Era
Big Banks Rebuild in Hong Kong as Deal Volume Surges
Italy Considers Freezing Retirement Age at 67 to Avert Scheduled Hike
Italian City to Impose Tax on Visiting Dogs Starting in 2026
Arnault Denounces Proposed Wealth Tax as Threat to French Economy
Study Finds No Safe Level of Alcohol for Dementia Risk
Denmark Investigates Drone Incursion, Does Not Rule Out Russian Involvement
Lilly CEO Warns UK Is ‘Worst Country in Europe’ for Drug Prices, Pulls Back Investment
Nigel Farage Emerges as Central Force in British Politics with Reform UK Surge
Disney Reinstates ‘Jimmy Kimmel Live!’ after Six-Day Suspension over Charlie Kirk Comments
U.S. Prosecutors Move to Break Up Google’s Advertising Monopoly
Nvidia Pledges Up to $100 Billion Investment in OpenAI to Power Massive AI Data Center Build-Out
U.S. Signals ‘Large and Forceful’ Support for Argentina Amid Market Turmoil
×