At 6:10 a.m. on September 9, a 6.9 magnitude earthquake struck Morocco. According to the Moroccan Ministry of the Interior, the death toll caused by the earthquake has risen to 2,681, the number of injured has reached 2,501, and there are many missing people, although many search and rescue personnel have been dispatched, but in the face of the damage caused by this strong earthquake, human power in the face of nature, it is so powerless.
What caused the earthquake?
There are several tectonic plates on the Earth's surface, large areas of the planet's outer layers, which are pitted against each other. This movement has led to various geological phenomena such as earthquakes, volcanoes, mountains and the formation of ocean basins.
Moroccan tectonic activity mainly involves the convergence of the Eurasian and Nubian (African) plates. The squeeze of the Nubian Plate by the Eurasian Plate led to the formation of the Atlas Mountains that run through Morocco, Algeria and Tunisia.
Currently, collisions between plates shorten the Atlas Mountains, which explains seismic activity in the area. We know this because GPS measurements show that moving about 1 millimeter gets closer every year
This shortening and compression leads to so-called failures, huge frictions between the plates. These faults may have been the cause of this earthquake. Scientists believe these faults have been active for a long time, dating back millions of years.
In addition, as noted by different researchers, the High Atlas Mountains have unique geological features, with the Earth's outermost hard layer, the lithosphere, thinner than usual, plus an unusual uplift of the mantle. All of these features could have influenced the occurrence of this earthquake of high magnitude.
What is the history of earthquakes in Morocco?
Seismic activity and its phenomena, such as earthquakes, are not uncommon in Morocco.
Over the past thousand years, earthquakes affecting Morocco tend to occur mainly offshore in two regions, along the Azore-Gibralth Transition Fault and the Alvolan Sea, and the other offshore, along the Rif Mountains in northern Morocco and the High Atlas Mountains in northwestern Algeria. The number of earthquakes along the Atlas Belt is small, but not uncommon.
The worst recent earthquake in Morocco was in mid-1994, 2000, 200 and 2016, with magnitudes between 6.0 and 6.3. These earthquakes occurred in the most seismically active areas of Morocco, as well as in the western Mediterranean.
Historically, the devastating Agadir earthquake struck in February 1960 with a magnitude of 6.3. It is located near the border between High Atlas in the west and Antiatras in the south. Available data indicate that between 12,000 and 15,000 people died from this event. In addition, near the site of the most recent earthquake, another earthquake occurred in 1955, with an estimated magnitude of about 5.8.
Even earlier, before the seismometer was established, several major events were recorded in Morocco. These include the 1624 Firth earthquake, estimated at magnitude 6.7, and the 1731 Agadir earthquake, which had a magnitude of 6.4.
Why is the earthquake so destructive in Morocco?
Located at the junction of the Eurasian plate and the African plate, Morocco is an earthquake-prone area, and since 1079, Morocco has experienced more than 20 strong earthquakes that have caused major casualties.
Experts pointed out that in the past 50 years, the African plate on the south coast of the Mediterranean has been extremely active, and it is estimated that it will advance an average of 6 millimeters north every year, and it is the violent movement of this plate that has led to frequent earthquakes on both the north and south sides of the Mediterranean. The magnitude 6.9 earthquake southwest of Marrakech, Morocco, was a strong earthquake that occurred inside the African plate, and its epicenter was located in the Atlas Mountains, and the thrust fault system parallel to the Atlas Mountains was the main cause of the strong earthquake.
The Atlas Mountains stretch to the Mediterranean coast of Algeria, in this seismic belt, seismic activity above magnitude 6 has not been recorded for a long time, but it is not a good thing to record strong earthquakes, after all, the collision and stretching between plates will continue to accumulate energy, and when the energy accumulates to a certain extent, it will "gush out" in the weak part of the earth's crust, thus causing a very lethal earthquake.
According to relevant experts' estimates, the energy and destructive power released by the Moroccan earthquake are equivalent to the concentrated explosion of 25 nuclear bombs, which shows the power.
Can earthquakes be predicted?
Unfortunately, even if we now have a wealth of knowledge of seismology, we cannot predict earthquakes. In fact, many researchers believe that this is not possible in the future. What seismologists can do is determine where earthquakes are most likely to occur, and even determine the probability of earthquakes occurring and their uncertainty.
This is what we call long-term forecasting, based on specific seismic hazard studies in the region. They are based on historical and instrumental knowledge of past seismic activity in the area, as well as the presence and knowledge of active tectonics (faults) that can produce earthquakes. The more people know about these two topics (seismicity and active faults in the area), the more they know about possible future seismic activity in the area and the less uncertainty there is.
In addition, seismic hazard studies include studies of near-surface soil conditions and building characteristics, which can help assess the damage potential of a potential earthquake.
For now, our best tool for mitigating the effects of earthquakes is to conduct reliable earthquake hazard research. These results must be incorporated into national building codes. In this way, engineers can incorporate seismic safety into building design. Building codes need to consider several factors, including the properties of the soil, how seismic waves move, and how the soil amplifies its movement during an earthquake. In addition, the expected shaking of the ground can also affect the behavior and damage of the building. These factors vary from city to city and sometimes from region to region.
Seismologists know that earthquakes rarely cause direct casualties, but buildings do. In areas with high seismic risk, buildings lacking regulation and structural support are potential killers for humans. Therefore, building codes must be mandatory and should be updated regularly. As more and more is known about seismic geology and the impact of earthquakes on buildings, building codes must be updated regularly, which is the best way to mitigate the impact of these catastrophic phenomena on human society, without being fundamentally immune to the threat of earthquake disasters.
#Autumn Life Punch Season# #摩洛哥强震破坏力相当于25枚核弹#