A powerful earthquake struck western Mexico on Monday, leaving at least one person dead and sparking panic hundreds of kilometers away in Mexico City on the anniversary of two devastating tremors. The quake — magnitude 7.7 according to the national seismological agency — shook buildings and sent people rushing out into the streets of the capital. “I thought I would have a heart attack!” said Gabriela Ramirez, a 58-year-old resident of Mexico City, where many remain traumatized by an earthquake five years ago that killed several hundred people. “This area is very vulnerable because many build…