A new cluster of large earthquakes began in 2004, and now scientists are questioning whether an even bigger one is yet to come, according to a new report by Eqecat, a risk modeling firm in Oakland, Calif.
Researchers have found that big earthquakes tend to occur in clusters over time. The number of earthquakes of magnitude 8.6 and greater last spiked between 1950 and 1965. Now, researchers think the earth may be in the middle of a new cycle of large earthquakes, the Eqecat report says.
The new cluster began with the 9.1 magnitude earthquake in the Andaman and Nicobar Islands near India. The Dec. 24, 2004, earthquake and tsunami killed about 280,000 people and was the most powerful earthquake in 40 years. Other large earthquakes since then include the:
• 7.9 Eastern Sichuan China earthquake in 2008.
• 6.3 L'Aqila, Italy, earthquake in 2009.
• 7.0 Port-au-Prince, Haiti, earthquake in 2010.
• 8.8 Maule, Chile, earthquake in 2010.
• 7.1 Darfield earthquake in 2010 and the 6.1 Lyttelton earthquake in 2011, both in New Zealand.
"The latest event of this destructive series of earthquakes was the 9.0 Tohoku-oki, Japan, earthquake that occurred in March 2011 and generated a massive tsunami that devastated the northeastern coast of Honshu," Eqecat researchers write. "This apparent global clustering of damaging earthquakes is raising concerns that our planet might experience even more catastrophic temblors in the near future."
The report is the first of three by Eqecat that will examine the different contexts of earthquake clustering. The second report will focus on clusters of aftershock sequences, and the third will examine fault-based models of earthquake clustering.