As the countries respond to the tragedies, many people are turning to scientists to learn why this series of tremors was so deadly. TECTONIC BOUNDARIESBoth Colombia and Venezuela sit atop several intersecting tectonic plates. The tremors in both Colombia and Venezuela were strike-slip earthquakes caused by horizontal shifts in the Earth's crust, producing lateral shaking that poses severe risks to structural integrity. Preliminary findings indicate that Venezuela's June earthquakes occurred along a different fault line. "Global sharing of data is very, very important because most earthquakes occur on tectonic plate boundaries that are always near political and continental boundaries."