Could It Happen Here?
What a methane seep might mean for us
(page 1 of 4)
The San Diego skyline (above), and a Japanese village devastated by the 2011 Tohuku earthquake and tsunami (below)
On December 26, 2004, a magnitude 9.3 earthquake struck off the Northwest coast of Sumatra. An upward thrust, deforming the ocean floor, sent tremendous energy into the water beneath the Indian Ocean. Over a period of several minutes, a 1,000-mile fault violently pushed underneath another tectonic plate. This massive displacement of enormous quantities of ocean water generated the deadliest tsunami event in history, striking shores far across the Indian Ocean from Indonesia to Sri Lanka, India, and Thailand, and claiming a death toll of more than a quarter of a million people.
On March 11, 2011, a 45-foot tsunami hit the coast of Japan, breaching the walls of the Fukushima Daiichi Nuclear Power Station, disabling the power supply and disrupting the cooling of three reactors, commencing a complete meltdown over the next three days. The tsunami inundated 1,500 square miles. Shifting tectonic plates under the ocean registered a magnitude 9.0 earthquake that moved the sea floor up as much as 15 feet over an area the size of Connecticut. The tsunami destroyed more than a million homes and buildings and took upwards of 19,000 lives.
These tsunami are not rounded, cresting waves, but powerful walls of churning seawater, smashing boats into bridges and sweeping trucks through buildings like tiny models made of balsa wood, laying to waste everything in their paths. Watching the inundation of dark, debris-heavy water in its unstoppable sweep forward, the obvious question arises: “Could this happen here?”
The short answer is: No, not exactly. The rest of the story begins with “But…”
Could This Happen Here?
On a clear day, looking out to sea from the tip of Point Loma, there can be seen a picturesque series of small islands. Bordering Mexican waters are the Coronados, and just north are the San Clementes. Further up the coast, alongside Orange and Los Angeles counties, is Santa Catalina. The Channel Islands dot the coast off Santa Barbara.
We tend to understand our world and our place in it based on what we can see. But there are much taller mountains under the ocean than above it. Those islands running north along the Southern California coast are in fact the peaks of a long undersea mountain range. The sides of these islands are made up of weak rock ledges, made of fault-fractured rocks and loose sand.