Terremoto literally translates to "earthquake". It's a powerful and dramatic word used to describe a force of nature.
In this upbeat song, Álvaro Soler uses it as a metaphor to describe his personality. When he sings "Soy un terremoto" (I am an earthquake), he's telling us he is full of unstoppable energy, passion, and a powerful desire to live life to the fullest.
Álvaro Soler's "Libre" is a massive celebration of living life on your own terms. He lays out his philosophy right from the start: he'd rather take a brush and paint and "dibujar en color lo que siento" [draw what I feel in color]. He wants a life with "Complicaciones sí / Aburrimiento no" [complications yes, boredom no], which is a pretty bold way to say you'd rather have an interesting life than an easy one. He describes himself as a force of nature, an earthquake even, declaring "Soy un terremoto / Tengo ganas de vivir" [I'm an earthquake / I have the will to live]. It's all about embracing energy, creativity, and looking forward, or "Mirando pal' frente" [looking forward], completely "Libre de preocupación" [free from worry].
This isn't just about being wild and crazy, though. He makes it clear he wants his "Pies en el suelo" [feet on the ground] and values his family. The ultimate goal is to be able to look back and "saber que he vivido" [know that I have lived], remembering all the luck he's had. The song also brings in a romantic element, a promise to a partner to share this life: "Te llevaré en mi corazón / Contigo quiero amanecer" [I will carry you in my heart / With you I want to wake up]. It's a powerful and joyful anthem about choosing your own path to happiness.