Three zones in Greece that can cause earthquakes of magnitude 7.7, as in Myanmar, and the four areas around Crete where a dangerous tsunami can occur.
Three dangerous zones near Greece
Kostas Papazachos, a geophysicist from Aristotle University of Thessaloniki, discussed the conditions necessary for a significant earthquake, like the one experienced in Myanmar. He emphasised that such intense seismic activity cannot occur just anywhere.
For an earthquake to reach extreme magnitudes, the geological conditions must be specific. Notably, a fault line extending several hundred kilometres is required, and this must be located within a suitable seismic zone.
When asked whether Greece has regions capable of producing such earthquakes, Papazachos identified three main areas of concern:
-
External Greek Arc: This zone starts from Kefalonia and continues south of Peloponnese, extending along the southern coasts of Crete. Its geological formations make it an area of particular interest in regards to seismic activity.
-
Northern Aegean Trench: This trench, especially the sections that lead towards Istanbul and the part connected to the Anatolian Fault, is known for its considerable length. The potential for significant earthquakes in this area has been noted due to its geological structure.
-
Amorgos Zone: While this last zone is marginal in comparison, it stretches across Amorgos and is still a point of interest for geophysicists looking to understand the earthquake potential in Greece.
Papazachos further clarified that Greece has not experienced earthquakes of such high intensity historically. He cited the 1956 Amorgos earthquake, which registered at 7.5 on the Richter scale. Unlike the catastrophic event in Myanmar, the repercussions were minimal in Greece. Contributing factors included the distance from the coast and the lack of high-rise buildings, which often amplify structural damage during seismic events.
According to Papazachos, significant earthquakes, such as the one in Myanmar, tend to create slow vibrations that heavily affect tall structures. Reflecting on history, he referenced an earthquake that struck southern Greece in 365 AD, measuring 8.2 on the Richter scale. He pointed out that at that time, there were no skyscrapers or multi-storey buildings, thereby lessening the potential destructiveness associated with such seismic events.
Key Points of the Zones Identified
-
External Greek Arc:
- Begins in Kefalonia.
- Stretches through Peloponnese and along Crete’s southern coast.
- Noted for its geological features conducive to large earthquakes.
-
Northern Aegean Trench:
- Leads towards Istanbul and intersects the Anatolian Fault.
- Contains significant lengths that can contribute to seismic risks.
-
Amorgos Zone:
- A lesser-known zone that still warrants attention.
- Positioned in Amorgos, with potential seismic implications.
Historical Context of Seismic Activity
The historical context of seismic occurrences plays a crucial role in understanding potential risks. The events described show that, while seismic activity can be severe, the local infrastructure and geographical factors greatly influence the outcome of such events.
For instance, the absence of large buildings during the 365 AD earthquake highlights why there was less damage compared to today’s standards.
Four tsunami risks around Crete
Four locations in Greece are now under scrutiny by UNESCO due to their potential risk for tsunamis. A recent meeting of specialised scientists in Paris, organised by the organisation, led to this assessment. These regions are believed to carry significant dangers, as tsunamis could cause widespread problems beyond localised impacts. Timely preparation by authorities is essential.
Meeting of Experts
Last week, 20 scientists convened at UNESCO’s headquarters to focus on the sources that could trigger major tsunami waves in the Mediterranean and the North Atlantic. This gathering gathered top experts in tsunami research as well as specialists in seismology, tectonics, and marine geology.
According to Gerasimos Papadopoulos, a seismologist and member of the Governing Council of the Greek Mediterranean University, this collaboration aimed to closely examine the threats posed to these geographical areas.
Major Geotectonic Structures
During the three-day conference, emphasis was placed on two large geotectonic structures. The first is the Hellenic Seismic Arc, which stretches from the Ionian Sea through Western Peloponnese, Crete, and finally to Rhodes. This area serves as a convergence boundary between the African and Eurasian tectonic plates, where intense clashes occur, resulting in the potential for powerful earthquakes.
The second geotectonic feature discussed spans from the Azores to Gibraltar. This area has a notable history of strong earthquakes resulting in considerable tsunamis, highlighting the ongoing geological activity and risk associated with it.
Tsunami Ready Initiative
UNESCO advocates for a series of actions necessary for identified regions to be designated as “Tsunami Ready.” These actions include establishing early warning systems, engaging in community preparedness, and ensuring proper communication channels are in place. Educating local populations about the signs and risks of tsunamis is crucial for reducing potential impacts.
Key Elements for Tsunami Readiness:
- Development of effective warning systems
- Community training and awareness
- Regular drills and simulations to prepare locals
- Clear communication strategies to inform residents
Areas of Concern
The four locations identified by UNESCO that are particularly at risk of tsunamis are crucial to monitor and prioritise for safety measures. Three of these regions are in close proximity to Crete. Given the seismic activity in the Mediterranean, these coastal areas could face threats from generated waves due to earthquakes or volcanic activity.
- Western Peloponnese
- Crete
- Rhodes
- Additional coastal areas based on geological studies
About the map:
1) SOUTH-WEST OF CRETE:
The sea area in the Nopodytika of Crete, where the strongest earthquake ever recorded in Europe occurred in 365 AD. The earthquake is estimated to have had a magnitude of 8.5 Richter, causing great damage. The tsunami is estimated at 12 metres high for Crete, where more than 100 settlements were destroyed.
There was also severe damage in the Peloponnese and the Mediterranean region, as far as the Nile Delta. Markelinos’ description is typical, writing, among other things, that “the ships climbed onto the roofs of the houses”. The ruins discovered during archaeological excavations in Kissamos, Eleftherna and Gortis are attributed to this earthquake.
2) NORTH OF CRETE:
The area between Santorini and Amorgos, where the largest tsunami of the 20th and 21st centuries occurred in the Mediterranean on 9 July 1956. Caused by a devastating earthquake with a magnitude of 7.7 Richter. Finally, two other major tsunamis originated in the same area of the southern Aegean.
The first is due to the famous Minoan explosion, the largest explosion known in human history. This occurred in the spring of 1613 BC.
In the first 24 hours after the explosion, all living creatures within a radius of 100 kilometres from the island were destroyed and entire islands devastated, while the phenomenon created the caldera of Santorini.
The second tsunami in the region occurred in 1650 AD due to an underwater explosion in Santorini and the sea began to spew out red-hot lava. Clouds, smoke, fumes, fire and lightning filled the sky. The tsunami reached a height of 20 metres.
3) SOUTH OF CRETE:
The southern sea area off Crete, for which events in the past are not known, offers the potential for a strong earthquake or tsunami in the future.
In May 2020, there was a magnitude 6.6 earthquake in this area south of Ierapetra, accompanied by a small tsunami.
4) BETWEEN CRETE AND RHODES:
The sea area in eastern Crete, between Crete and Rhodes, where a very strong earthquake also occurred in 1303 AD, with an estimated magnitude of 8 Richter, accompanied by tsunamis up to 10 metres high. The earthquake, for which there are many references to Byzantine, Arabic and Latin historical sources, destroyed cities and killed many people.
A few minutes after the quake, the tsunami hit Karpathos and Rhodes with terrible force. An hour later, Crete was hit by waves 5 metres high. In Alexandria, the coastal zone was flooded and the harbour facilities damaged.
An hour and a half after the earthquake, the tsunami hit the area that is now Israel, where many people drowned.
Impacts of a Tsunami
The consequences of a tsunami can be devastating. Not only can they cause extensive destruction to infrastructure, but they also pose a significant risk to human life. The environmental effects can alter coastal ecosystems, leading to long-term challenges in recovery.
Potential Impacts Include:
- Destruction of homes and buildings
- Inundation of agricultural land
- Loss of life and injury
- Economic disruptions due to damage
Continuous Monitoring and Research
Ongoing research and monitoring are vital in understanding seismic threats in the region. The work conducted by these scientists contributes to a greater understanding of how tectonic shifts and other geological activities can lead to tsunami formation.
Research Focus Areas:
- Monitoring seismic activity
- Studying past tsunami events
- Evaluating the geological features of at-risk areas
Following the expert analysis, authorities in Greece have a responsibility to improve safety efforts in these vulnerable regions. The collaboration between countries and organisations is fundamental to achieving safety goals effectively.
Collaborative Efforts
Collaborative efforts involving the Mediterranean nations are necessary to establish a comprehensive approach to tsunami risks. Sharing data, strategies, and best practices can foster a more proactive stance against potential disasters. Countries in the Mediterranean must work together to address these shared vulnerabilities.
Preparedness Strategies
In addition to immediate warning systems, strategies to improve community resilience include:
- Establishing evacuation routes
- Conducting community drills
- Raising public awareness about tsunami risks
Government investments in infrastructure upgrades can significantly enhance the capacity to deal with tsunami threats. Increased funding for research and emergency services will support the implementation of necessary changes to infrastructure.
Authorities and communities should work hand in hand to engage in systematic planning to mitigate the impacts of a tsunami, elevating the importance of community involvement in readiness programmes.
Educational Initiatives
Education plays a key role in emergency preparedness. Programmes designed to inform citizens about tsunami risks, response actions, and safety practices can save lives.
Incorporating this information into school curricula or community workshops can foster a culture of awareness and preparedness.
Future Challenges
Greece faces the ongoing challenge of managing its coastal regions while addressing the risks posed by natural disasters. As climate change continues to influence weather patterns and geological activity, the potential for increased seismic activity may also rise.
Authorities are tasked with not only responding to current dangers but also anticipating future threats through planning and adaptation. This requires continual commitment from governments, scientific communities, and citizens alike.
Summary of Recommendations
To improve Tsunami Readiness in these four crucial regions, the following steps are recommended:
- Enhance early warning systems through technology and community engagement.
- Conduct regular training sessions for emergency responders and locals.
- Develop effective communication strategies to ensure timely dissemination of information.
- Engage residents in educational initiatives to promote awareness of risks and safety procedures.
Implementing such recommendations can significantly reduce the potential impact of a tsunami in Greece, particularly in areas surrounding Crete, where risks are notably high. The collaboration between UNESCO and local authorities is an essential step towards achieving these goals and enhancing community safety.
Frequently Asked Questions
Which three seismic regions in Greece are most likely to produce a 7.7 magnitude earthquake?
The three main seismic areas in Greece that could potentially generate an earthquake of 7.7 on the Richter scale include specific faults known for their tectonic activity. These zones have been identified by researchers studying seismic patterns and historical earthquake occurrences.
Has Crete ever faced an earthquake comparable in magnitude to the 7.7 events seen in Myanmar?
Crete has experienced significant seismic activity in the past, but it has not recorded an earthquake reaching the same magnitude as the 7.7 events reported in Myanmar.
While large earthquakes have occurred, a direct comparison to such high-magnitude events remains complex and specific data is required.
How does Crete’s seismic risk measure against other earthquake-prone areas in Greece?
Crete’s seismic risk is considered substantial, especially when compared to other high-risk regions in Greece.
The island sits on a tectonic boundary, making it susceptible to earthquake activity similar to other parts of the country that are known for their geological instability.
What procedures are established for earthquake readiness and response in Crete?
Crete has implemented various measures for earthquake preparedness, including public education campaigns, building regulations, and emergency response plans.
Local authorities work to ensure that residents are aware of safe practices during an earthquake and know how to respond effectively.
Is it possible to forecast when the next significant earthquake might happen in Crete or elsewhere in Greece?
Currently, predicting the exact timing of future large earthquakes remains challenging.
While scientists can identify areas at risk and monitor seismic activity, no reliable method exists to predict the precise moment when an earthquake will strike.
What historical accounts document major seismic events in Crete or other parts of Greece?
There are numerous historical records of significant earthquakes in Crete and across Greece. These accounts provide insights into past seismic activity. They help researchers understand patterns and improve future preparedness strategies.
