Approximately 500,000 Earthquakes are registered across the globe every year, according to US Geological Survey (USGS). As Colombia reels from one of the strongest earthquakes in its recorded history that killed at least 250, just weeks after more than 6,000 deaths in twin quakes in neighboring Venezuela, many turned to scientists to learn how to restrict or limit the destruction.
The earth is a dynamic planet; it rotates, orbits the sun and is always in a tumultuous state under the surface. Regions in the Pacific Ring of Fire, the Himalayas, the Mediterranean, Central America and the Caribbean are particularly at risk due to regular tectonic movement, NewsVoir reported.
An earthquake's magnitude is measured by a logarithmic scale that gets bigger with every unit, so that a quake of magnitude 7 is more than 30 times stronger than one of magnitude 6.
Major earthquakes can often also cause aftershocks, a grave risk for those returning to structures damaged by the first impact. Colombia had registered more than 100 aftershocks by Tuesday afternoon. Both of Venezuela's June earthquakes occurred along a separate fault, initial data shows. The second was larger, leading the U.S. Geological Survey to classify the initial 7.2 quake as a "foreshock."
Terrain, Infrastructure Hold Key
Countries particularly prone to earthquakes, such as Chile and Japan, enforce regulations to ensure buildings can withstand fierce shaking, with use of strong yet flexible designs that let them sway without snapping.
Informal housing or poor investment in engineering, however, can be devastating when quakes hit densely-populated cities. The 2010 Haiti earthquake is estimated to have killed more than 300,000 at a cost equivalent to 120 per cent of the prior year's GDP. Colombia began designing earthquake-resistant construction in the 1970s and adopted its first building code in 1984 after a destructive quake in Popayan. Its current code was established in 2010.
Prieto said location, materials and building code compliance are key to making earthquake-resistant cities, adding he believed this week's destruction should be studied to improve existing building regulations.
Another key factor is soft terrain. Mexico City, built on a dried-up lake bed, is vulnerable even to faraway earthquakes because of the amplifying effect of the soil structure. Venezuela's coastal area of La Guaira, built on soft, loose soil, was hard hit in June, as were Colombia's western valleys this week.
Planning Is Required
Imposing costly and hard-to-implement building codes in areas rarely hit by serious quakes can be difficult, while region-specific risks are also tough to guard against, said Suzan van der Lee, a seismologist at Northwestern University.
"Our earthquake record is long but not so long that we've seen every possible type of shaking," she told Reuters. "We're often surprised when earthquakes happen in ways we haven't seen before."
Building networks of seismic stations and sharing data across borders is key to help lower risks, van der Lee added.
"Global sharing of data is very, very important because most earthquakes occur on tectonic plate boundaries that are always near political and continental boundaries."
