
The earth continues to rock and roll in the Philippines a day after a powerful 7.6 earthquake struck. In just the last 24 hours, USGS reports there have been more than 140 earthquakes near the epicenter of yesterday’s earthquake, with many of those aftershocks quite strong too. 85 of the last earthquakes were over 2.5 with many over 5.5. A strong 6.9 aftershock struck earlier today, one of many strong quakes to strike in the aftermath of yesterday’s large seismic event.
According to the Associated Press, a pregnant woman died after she, her husband and daughter were hit by a 15-feet concrete wall that collapsed in their neighborhood. According to Shieldon Isidoro, the disaster mitigation chief for Tagum City, the family jumped out of their home as the ground shook. Her husband and daughter were injured too. Two other children and their parents jumped from a second-floor window in panic as their house swayed but were not injured after landing on a grassy lot, said Isidoro, who was at his home when the ground started to shake.
“Initially the swaying was weak. Then it quickly became stronger and I could hardly stand. My perfume bottles fell off a table, pictures on my wall swung and I heard people screaming outside: ‘Get out, get out, earthquake, earthquake!”’ Isidoro said.
In addition to the earthquakes, there were also concerns about tsunami throughout the Pacific. Alerts were issued by authorities in Japan and Australia while the Honolulu, Hawaii-based National Weather Service’s Pacific Tsunami Warning Center (PTWC) issued their own bulletins to people in Hawaii and the U.S. West Coast.
While a minor tsunami was generated near the tsunami which amounted to being less than 6″ high, it became clear there was no threat of a Pacific-wide tsunami and the appropriate government agencies relayed that fact.
While there was a risk of a local tsunami, the the PTWC said the threat didn’t travel far from the epicenter of the earthquakes. “Based on all available data, a destructive Pacific-wide tsunami is not expected,” said the PTWC in their bulletins.
Tsunamis are giant waves caused by earthquakes or volcanic eruptions under the sea. Out in the depths of the ocean, tsunami waves do not dramatically increase in height. But as the waves travel inland, they build up to higher and higher heights as the depth of the ocean decreases. According to the National Ocean Service, the speed of tsunami waves depends on ocean depth rather than the distance from the source of the wave. Tsunami waves may travel as fast as jet planes over deep waters, only slowing down when reaching shallow waters. While tsunamis are often referred to as tidal waves, this name is discouraged by oceanographers because tides have little to do with these giant waves. The location, depth, movement, and intensity associated with today’s earthquake wasn’t enough to trigger a tsunami from today’s earthquake.
While a 7.0 magnitude earthquake did force the PTWC to issue another round of tsunami-related bulletins today, there remains no threat of tsunami at this time from any of this earthquake activity. Should that change, the PTWC would issue fresh advisories or warnings.