Earthquakes rock the Phillipines

Manila (dpa) – Three strong earthquakes rocked the southern
       Philippines early Saturday but the origins of the tremors were too
       deep below the sea to cause damage or injuries, a government agency
       said.
    
          The Philippine Institute of Volcanology and Seismology (Phivolcs)
       said the first tremor was recorded early Saturday with a magnitude of
       6.9, the second registered 6.7, while the third reached 7.1.
    
          The agency said the strong earthquakes occurred at intervals of
       about one hour, with epicentres located between 94 and 98 kilometres
       south-west of Cotabato City, 960 kilometres south of Manila.
    
          The quakes were tectonic in origin, the institute said.
    
          Renato Solidum, the head of Phivolcs, said the depth of the three
       earthquakes was between 570 and 630 kilometres below sea level, too
       deep to cause damage or tsunamis.
    
          “Essentially, [in a] large-magnitude earthquake, which would come
       from a very deep source, the shaking it would generate at the surface
       will be much less because [of] the thick pile of rock that the energy
       will encounter as it moves into the surface. So it will not be
       damaging,” he said.
    
          “There will be no tsunami generated by these events,” he added.
    
          The institute said the earthquakes were felt in some areas
       throughout the country at low intensities.
    
          The last major earthquake hit the Philippines in 1994, killing
       more than 70 people. The magnitude-7 quake triggered a tsunami in the
       central island of Mindoro.
    
          In 1990, a powerful earthquake measuring 7.7 hit the northern
       Philippines, killing more than 1,200 people and destroying hundreds
       of buildings.
    
          The Philippines sits on the so-called Pacific Ring of Fire, where
       continental plates meet, causing frequent seismic and volcanic
       activity.