“Even if we say ‘we are prepared,’ no country knows on what day it will be hit, society is not well trained to react, and to that is added the fact that most of the construction is informal,” warns geologist Osiris de León
SANTO DOMINGO. – Dominican geologist Osiris de León warned that the Dominican Republic faces a severe seismic risk due to the combination of two large active faults, soils that amplify seismic waves in the Cibao Valley, and 70% informal construction throughout the country.
The statements were made in interviews on the radio programs Ahora por la Súper 7 FM and El Rumbo de la Tarde por Rumba FM, within the framework of the analysis of the earthquake that affected Venezuela last week and that as of yesterday, Sunday, had left a toll of more than 1,500 dead and thousands missing.
According to De León, the island of Hispaniola has two seismic faults capable of generating large-magnitude earthquakes. The first is the Enriquillo-Plantain Garden fault, which runs through Jimaní, Barahona, and southern Azua, the same fault that caused the Port-au-Prince earthquake of January 12, 2010, which killed 316,000 people. The second is the northern fault, which runs north of Monte Cristi, Puerto Plata, Sosúa, Cabarete, Río San Juan, and Samaná.
The geologist pointed out that the Cibao Valley presents an additional risk factor: its soil is composed of a thick layer of soft marine clay that amplifies seismic waves. "The waves are amplified, multiplying the thrust, the force of the movement, and then they end up causing structures to collapse," De León explained on Super 7 FM.
As a historical precedent, he cited the earthquake of December 2, 1562, whose epicenter was on the Atlantic coast but which completely destroyed Santiago and La Vega due to the response of the valley soils. Santo Domingo, built on limestone, suffered no damage.
De León specified that the risk extends from Piedra Blanca and Bonao to Monte Cristi, along the entire valley. "Soils that are good for agriculture are bad for the buildings constructed on them during an earthquake," he stated.
70% informal construction
The geologist indicated that the most alarming and dangerous fact is that 70% of the buildings erected in the country are informal. He described the common practice of adding second and third floors, removing support columns, building walls without structural support, and constructing additions without any technical basis. "The day an earthquake hits, all of that will collapse," he stated in the interview on Super 7 FM.
De León directly linked this condition to the historical damage in comparable seismic events, such as the case of Haiti, where he identified three factors that multiplied the impact of the 2010 earthquake: the fault line ran right next to Port-au-Prince, the hypocenter was shallow, at a depth of 10 kilometers, and the structures were vulnerable. "He found a very vulnerable society, structures that were very vulnerable," he said on El Rumbo de la Tarde, on Rumba FM.
The lesson of Venezuela
De León used the Venezuelan case to illustrate the limitations of institutional preparedness. He asserted that Venezuela began its earthquake-resistant engineering program in the 1960s, following the Caracas earthquake of July 1967, which registered a magnitude of 6.5.
Since then, he has operated with a university specialization in earthquake resistance at the Central University of Venezuela, a foundation dedicated to the subject, and several active institutions. Even so, the June 2026 earthquake has so far resulted in more than 40,000 missing persons and the collapse of thousands of structures in Caracas, Maiquetía, Macuto, and La Guaira.
"They didn't expect to see so much destruction," De León told El Rumbo de la Tarde, explaining that the conceptual error was in designing structures to comply with the building code without evaluating the local seismic response of the soil.
"You haven't designed a structure for the floor, but a structure for the code. And those are two different things," he explained.
De León recalled that the seismic scale is logarithmic, not linear, so each unit that goes up multiplies the energy released by 32. The Dominican earthquake of August 4, 1946, with its epicenter in the Matanzas and Nagua area, reached a magnitude of 8.1, followed by an aftershock of 7.6.
"The difference between an 8 and a 7 is 32 times," he explained. "An 8 is 32 times larger than a 7 because the scale is logarithmic," he reiterated.
