Breaking news! Tonight, Mexico City (CDMX) was surprised by a micro-earthquake, which was felt mainly in the Benito Juárez borough. Where else was it felt? The tremor occurred this Monday, September 2, near the Valley of Mexico.
However, the National Seismological Service (SSN) reports that a micro-earthquake of magnitude 2.5 was also recorded in the Álvaro Obregón municipality, northwest of the municipality, during the night of Monday, August 2.
EARTHQUAKE Magnitude 2.5 Location 2 km NORTHWEST of V ALVARO OBREGON, CDMX 02/09/24 22:42:47 Lat 19.41 Lon -99.21 Pf 1 km
— National Seismological Institute (@SismologicoMX) September 3, 2024
Subsequently, two more earthquakes were reported with their epicenter in the Benito Juárez municipality, the first with a magnitude of 1.9 and the second with a magnitude of 1.4 southwest of the capital municipality.
EARTHQUAKE Magnitude 1.9 Loc. 1 km SOUTHWEST of BENITO JUAREZ, CDMX 03/09/24 00:13:18 Lat 19.40 Lon -99.17 Pf 1 km
— National Seismological Institute (@SismologicoMX) September 3, 2024
EARTHQUAKE Magnitude 1.4 Loc. 1 km SOUTHWEST of BENITO JUAREZ, CDMX 03/09/24 00:19:02 Lat 19.40 Lon -99.17 Pf 1 km
— National Seismological Institute (@SismologicoMX) September 3, 2024
What is a microseism? The reason why they are felt in CDMX
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According to the UNAM Institute of Geophysics, a microseism is a small magnitude earthquake that occurs in a specific area and lasts very short, just a few seconds. These are generated by small ruptures inside the earth, located near the surface, at a depth of about four or five kilometers.
There are several reasons why Mexico City is prone to experiencing microseisms. When talking about these movements, it is highlighted that the country’s capital is located on the Pacific Ring of Fire, a subduction zone with high seismic and volcanic activity; however, other factors are also mentioned such as:
- The Valley of Mexico is built on ancient lakes. This type of soil, known as lacustrine, amplifies seismic waves, making tremors felt with greater intensity and duration.
- The extraction of water from the subsoil and large constructions have also caused an increase in these small movements.
- The presence of volcanoes in the vicinity of the country’s capital, such as those in the Sierra de Santa Catarina, also influences local seismic activity.
Why did the seismic alert not sound with today’s micro-earthquake?
Although hundreds of residents of the capital reported that the micro-earthquake of September 2 was felt quite strongly, the seismic alert was not activated. Why? According to the Mexican Seismic Alert System (
SASMEX
), the alert is issued only in situations where the earthquake represents a significant threat, and it does not detect local movements.
Another reason is that the alert is only activated if the earthquake has a magnitude greater than 5.0 and occurs less than 250 kilometers from the city.
Earthquake Mexico City today
Micro-Earthquake Hits Mexico City: Understanding the Phenomenon and Its Implications
Breaking news has just emerged that Mexico City (CDMX) was surprised by a micro-earthquake, which was felt mainly in the Benito Juárez borough. The tremor occurred on Monday, September 2, near the Valley of Mexico. However, this was not an isolated incident, as the National Seismological Service (SSN) reports that a micro-earthquake of magnitude 2.5 was also recorded in the Álvaro Obregón municipality, northwest of the municipality, during the night of Monday, August 2 [[1]].
Subsequently, two more earthquakes were reported with their epicenter in the Benito Juárez municipality, the first with a magnitude of 1.9 and the second with a magnitude of 1.4 southwest of the capital municipality [[2]]. These micro-earthquakes have left many residents wondering why they did not receive a seismic alert and what exactly these small magnitude earthquakes entail.
What is a Microseism?
According to the UNAM Institute of Geophysics, a microseism is a small magnitude earthquake that occurs in a specific area and lasts very short, just a few seconds. These are generated by small ruptures inside the earth, located near the surface, at a depth of about four or five kilometers. In Mexico, there are very strong earthquakes with far-reaching consequences, and earthquakes with a magnitude of over 8.0 can destroy numerous houses within a radius [[3]].
Why are Microseisms Felt in CDMX?
There are several reasons why Mexico City is prone to experiencing microseisms. The country’s capital is located on the Pacific Ring of Fire, a subduction zone with high seismic and volcanic activity. Additionally, the Valley of Mexico is built on ancient lakes, which amplifies seismic waves, making tremors felt with greater intensity and duration. The extraction of water from the subsoil and large constructions have also caused an increase in these small movements. Furthermore, the presence of volcanoes in the vicinity of the country’s capital, such as those in the Sierra de Santa Catarina, also influences local seismic activity.
Why did the Seismic Alert not Sound?
Although hundreds of residents of the capital reported feeling the micro-earthquake of September 2, the seismic alert did not sound. This is because the seismic alert system is designed to respond to earthquakes with a magnitude of 5.0 or higher. As the magnitude of the micro-earthquakes was below this threshold, the alert system did not trigger. However, it is essential to note that even small magnitude earthquakes can cause damage and should not be taken lightly.
micro-earthquakes are a common phenomenon in Mexico City due to its location on the Pacific Ring of Fire and the geological characteristics of the Valley of Mexico. While the seismic alert system did not sound for the recent micro-earthquakes, it is crucial to remain vigilant and prepared for any seismic activity. By understanding the causes and implications of microseisms, residents of CDMX can take necessary precautions to ensure their safety.
References:
Mexico City earthquake today
Breaking News: Micro-Earthquakes Hit Mexico City
A series of micro-earthquakes recently struck Mexico City, leaving residents shaken but relieved that the tremors were not more severe. The epicenters of the quakes were located in the Benito Juárez and Álvaro Obregón municipalities, with magnitudes ranging from 1.4 to 2.5. But what exactly are microseisms, and why are they so common in Mexico City?
What is a Microseism?
According to the UNAM Institute of Geophysics, a microseism is a small magnitude earthquake that occurs in a specific area and lasts only a few seconds. These micro-movements are generated by small ruptures inside the earth, located near the surface, at a depth of about four or five kilometers. They are often felt in areas with high seismic activity, such as the Pacific Ring of Fire, where Mexico City is located.
Why are Microseisms Felt in CDMX?
Mexico City is prone to experiencing microseisms due to its unique geology. The city is built on ancient lakes, which creates a type of soil known as lacustrine. This soil amplifies seismic waves, making tremors feel more intense and longer-lasting. Additionally, the extraction of water from the subsoil and large constructions have also contributed to the increase in these small movements. The presence of nearby volcanoes also plays a role in the city’s seismic activity.
Recent Earthquakes in Mexico
Mexico has a history of devastating earthquakes, including the magnitude 7.1 earthquake that struck central Mexico in 2017, killing over 200 people and leveling buildings [[1]]. Another powerful earthquake in Mexico City in 2017 left at least 220 people dead and caused widespread destruction [[2]]. However, in recent years, Mexico has experienced a significant number of small earthquakes, with 4 earthquakes in the past 24 hours, 13 in the past 7 days, and 81 in the past 30 days, according to Earthquake Track [[3]].
Seismic Alert System
Despite the recent micro-earthquakes, the seismic alert system did not sound, leaving many residents wondering why. The National Seismological Service (SSN) is responsible for monitoring seismic activity and issuing alerts to the public. However, the system is only triggered by earthquakes with a magnitude of 5.0 or higher, which is why the micro-earthquakes did not trigger an alert.
Conclusion
Mexico City’s unique geology and location on the Pacific Ring of Fire make it prone to experiencing microseisms. While these small earthquakes may cause concern, they are a reminder of the importance of earthquake preparedness and the need for continued monitoring and research into seismic activity. By understanding the causes of microseisms, we can better prepare for larger earthquakes and work towards creating a safer, more resilient city.
