TSUNAMI! Destructive waves! The tsunami is a sequence of waves that can reach heights of several tens of meters and sweep away everything in its path; it is produced mostly by strong submarine earthquakes occurred near the coastal area In Mexico, during the last 280 years, 65 tsunamis have hit the Pacific coast, with waves up to 10 meters in height, therefore, it is important to be informed about the directions of Civil Protection authorities At any sign, attend directions of the Civil Protection authorities Preventive measures IF YOU LIVE NEAR THE COAST OR IF YOU TRAVEL TO THE BEACH • Investigate the height above the sea level of the place where you live • Identify evacuation routes towards high places • Prepare a family evacuation plan and protect children, elder people and animals • Identify tall buildings and places that will serve you as temporary shelter Learn more Center for Scientific Research and Higher Education of Ensenada, Baja California www.cicese.edu.mx National Center for Disasters Prevention www.cenapred.gob.mx Tsunami Warning Center digaohm.semar.gob.mx/CAT/codes/ centroAlertasTsunamis.html Recommendations WARNING SIGNS AT THE BEACH WHAT TO DO IF A TSUNAMI IS COMING? • A strong earthquake, although not all of them produce a tsunami • The sea goes away from the beach exposing the seabed • The water becomes foamy 1 • Keep calm 2• Stay away from the beach, rivers, streams, wetlands or coastal lagoons and be sheltered in the highlands 3• Do not stop to observe the seafloor #PrevenirEsVivir MOVING MEXICO INTO PREVENTION 4• If you are on a boat, refrain from reaching a port; at offshore the risk is lower 5• Do not use your vehicle to evacuate 6• Avoid bridges over water bodies Source: National Center for Disaster Prevention Tsunami or Maremoto Comparativa de velocidad de las olas con medios de transporte The earthquake is the alert! What is it? Stages of a tsunami Natural phenomenon which destroys littorals due to wave action caused by a strong earthquake in the seabed. The Japanese word tsunami means "harbor wave". It is also called maremoto, a Latin word for "sea in motion” Generation Earthquakes lift vertically the earth crust at the seabed Mexico is at the "Circum-Pacific belt" or "Ring of Fire", geologically active zone that causes 80% of the tsunamis Propagation Tsunami waves travel at high speeds (800 km/h) on the open sea, for example, with 5,000 meters depth. This velocity decreases to 35 km/h when approaching the coast, with 10 meters depth Flooding The waves increase when they reach the coast. Not always the first wave is the highest, sometimes it is the third or fourth one, and they devastate everything on its path, reaching up to 10 km inland Location of Circum-Pacific Belt or Ring of Fire Trenches 800 km/h 250 km/h 100 km/h 35 km/h 5,000 m 500 m 100 m 10 m Depth Ocean bed Types of seismic tsunamis Local: They originate along the coast and penetrate large distances inland in a short time Regional: They originate 1,000 kilometers away from the country and arrive within a time span of three hours Distant or transoceanic: They originate in the western margin of the Pacific Ocean and take between eight and ten hours to reach the coasts of Mexico. They can cause great damage if the magnitude of the earthquake is greater than eight Hazard of tsunamis in Mexico High* Medium Low *Distant tsunami generating-and-receiving area Alerts Due to the hazard of tsunamis in Mexico, the National Tsunami Warning System (SINAT) was created, hosting the Tsunami Warning Center (CAT) in charge of the Mexican Navy, to analyze and process both the seismic and sea level data in real time. The CAT sends bulletins to the Civil Protection authorities in order to alert the population promptly