Earthquakes demonstrate how much damage in Mexico
Earthquakes demonstrate how much damage in Mexico:- Two big earthquakes were a tragic reminder in Mexico in last month that the country sits atop one of the most seismically active places on Earth. In particular, the magnitude 7.1 Puebla tremor on 19 September demonstrated Mexico’s vulnerability, causing serious damage in Mexico City and taking more than 270 people lives.
However, Mexico’s most lethal earthquake remains the 1985 Michigan earthquake of magnitude 8, which occurred 32 years earlier before, to the day, and as many as 10,000 people were killed. Strangely, many of the buildings that survived in 1985 succumbed to the tremors from the magnitude 7.1 last month. That’s because of two earthquakes produced different kinds of shaking and destruction
Although previous month’s 7.1 was 30 times less powerful than the magnitude 8 in 1985, its epicenter was very close to Mexico City: 130 kilometers away compared with 400. This distance explains the differing damage patterns between the two earthquakes.
It is the low “booming bass” waves that travel across long distances. They cause the ground flat surface to roll like a boat riding in rough seas and tall buildings are especially vulnerable to this motion. In 1985, it was the tallest buildings (between five and 20 storeys) that suffered the worst damage.
Earthquakes such as the event of 7.1 magnitude previous month produce intense “jerky” shaking. This high-frequency movement (which diminishes over distance) is more effective for shorter buildings (less than six storeys). So, in this case, the taller buildings swayed violently but remained standing, while the smaller buildings, many of which had survived the earthquake in 1985, quickly became heaps of rubble.