Central Idea
- A devastating earthquake struck Morocco, resulting in significant casualties and damage.
Details of the Moroccan Earthquake
- Shallow Epicenter: The quake’s epicentre was near the town of Ighil, approximately 70 km southwest of Marrakech. It was considered fairly shallow, with varying depth estimates.
- Higher Energy: Shallow earthquakes are typically more dangerous as they carry more energy, making them more destructive compared to deeper quakes.
Major Causes
- Tectonic Convergence: The earthquake resulted from the northward convergence of the African plate with the Eurasian plate along a complex plate boundary.
- Faulting: The USGS attributed the quake to oblique-reverse faulting at a shallow depth within the Moroccan High Atlas Mountain range.
- Fault Classification: Oblique-slip faults exhibit characteristics of both dip-slip and strike-slip faults, occurring in areas of compression where tectonic plates converge.
Why discuss this?
- Low Seismicity: Earthquakes are uncommon in North Africa, with low seismicity rates along the northern margin of the continent.
- Historic Strength: This earthquake was the strongest ever recorded in the mountainous region, catching Morocco unprepared for such an event.
- Construction Vulnerabilities: Many Moroccan buildings, especially in rural areas and older cities, are not constructed to withstand strong tremors.
What is an Earthquake?
- An earthquake is an intense shaking of the ground caused by movement under the earth’s surface.
- It happens when two blocks of the earth suddenly slip past one another.
- This releases stored-up ‘elastic strain’ energy in the form of seismic waves, which spreads through the earth and cause the shaking of the ground.
What exactly causes Earthquakes?
- As we know, the earth’s outermost surface, crust, is fragmented into tectonic plates.
- The edges of the plates are called plate boundaries, which are made up of faults.
- The tectonic plates constantly move at a slow pace, sliding past one another and bumping into each other.
- As the edges of the plates are quite rough, they get stuck with one another while the rest of the plate keeps moving.
- Earthquake occurs when the plate has moved far enough and the edges unstick on one of the faults.
- The location below the earth’s surface where the earthquake starts are called the hypocenter, and the location directly above it on the surface of the earth is called the epicentre.
