Spate of recent earthquakes 'not unusual'

SINGAPORE — A 5.4-magnitude earthquake struck Nepal earlier this week. This came after two tremors each registering close to 7 on the Richter scale jolted China and Japan last week. And on Nov 14, New Zealand experienced a 7.8-magnitude tremblor.

Is the recent rash of quakes in the Asia-Pacific region part of a larger geological phenomenon? No, said experts quizzed by TODAY. Apparently, despite their quick succession, these quakes are neither unusual nor related.

“There will be periods of quiescence and activity at the global scale for large earthquakes,” said Assistant Professor Christos Gouramanis of the National University of Singapore’s Department of Geography. “The occurrence of several large earthquakes in different areas over a short period of time (e.g. Japan and New Zealand) is not suggestive of a larger geological phenomenon at work.”

He added that the recent spate of quakes is arguably a “coincidence” as tremors occurring on different plate boundaries are not inherently related. Indeed, each of the four earthquakes that jolted the region this month occurred on different plate boundaries.

Similarly, Assistant Professor Christie Rowe told this paper in an e-mail interview that the recent tremors are not unusual according to the normal frequency of earthquakes in the magnitude 6-7 range. In fact, the geology expert with Canada’s McGill University said, there were fewer quakes of this size in 2016 than in some previous years.

Prof Rowe added that the occurrence of quakes appeared to be higher because of the increased human interest in this phenomenon and the concomitant spike in media coverage.

Professor Chris Goldfinger offered a more guarded assessment of the situation.

The marine geologist with America’s Oregon State University noted that while the random variability of fault-lines could generate earthquakes that happen to bunch up, “the reality though is that we know next to nothing about how the Earth system really works over larger spans of time and distance, and so we can’t really rule out global patterns that may currently be either random, or something we can’t explain.”

The quake that occurred off Fukushima last week invoked memories of the 2011 9.0-magnitude temblor in the same region that triggered a tsunami causing massive destruction and casualties.

Indeed, experts believe that last week’s tremor was an aftershock of the mega-quake five years ago. Prof Rowe said it is common for aftershocks to occur years after a major earthquake, especially one of the size of the Tohoku tremor.

So with the year-end holiday season upon us, should travelers avoid quake-prone countries like New Zealand and Japan or be extra careful if they go?

Prof Rowe told TODAY: “There is no reason for the public to worry any more than usual, unless they live very close to the site of a recent earthquake, where they will certainly be expecting some aftershocks in the days/weeks ahead.”

Prof Gouramanis has similar words of advice for would-be travellers to quake-prone areas.

He urged them to follow instructions from local authorities should an earthquake happen, adding that they should also be wary of the dangers caused by quakes such as landslides and tsunamis.