High seismic activity will last 10 years – seismologist
20 Mar, 2011 10:42
The magnitude-9.0 earthquake in Japan was one of the major events in the natural cycle of the planet's seismic activity, Evgeny Rogozhin, deputy director of the Institute of Physics of the Earth of the Russian Academy of Sciences told RT.
RT: You have made some controversial predictions in terms of future earthquakes. What exactly are they and what are they based on?Evgeny Rogozhin: I think that there is no direct connection between the earthquake in Japan and earthquakes that could happen on our territory. But this latest is one of the major events in the chain of earthquakes that recently happened on the planet. You all remember the earthquake on Sumatra in 2004. It was a major earthquake – magnitude 9.5. It was huge. Major loss of life, tsunami, etc. Then there were a number of other earthquakes – in India, where people also died, in China with the magnitude 8 and finally, in Chile last year – 8.8. And now this earthquake in Japan with a magnitude unheard of before in this country – 9.As you can see the process is taking place in different places on Earth. What does our country look like in this respect? In the last 15 years or so we've had about 15 major earthquakes in our Far East, so almost every year there was an earthquake.On the Kuril Islands, on Kamchatka, Sakhalin, in Koryak Okrug. So we had never seen such frequency before. Therefore we can say that we've witnessed a significant increase in seismic activity on Earth in the last 15 years. In the previous years, at least in the 1970s and 1980s there had not been so many major earthquakes. There was a calm period.The dangerous spots in our country are Kamchatka, many experts have been predicting earthquakes in its southern parts for a long time, and the Northern Kuril Islands. May be the Southern Kuril Islands now, considering the earthquake in Japan, because seismic activity can spread there.I also think that the North Caucasus is a very dangerous zone, because there haven't been any major earthquakes there for a very long time. There was a minor earthquake in 2008 in the Kurchaloisk region, but nothing serious in a really long time. So these I think are the most dangerous zones in Russia – Kamchatka, the Kuril Islands and the North Caucasus.RT: Are we witnessing an overall increase in seismic activity or is it just a volatile period? When did it start and when could be over?ER: I believe this period, like all processes on Earth, is of cyclic development. If we mention the middle of the 20th Century, it was also a period of more activity, with the great earthquake in Chile in 1960 – with a magnitude of more than nine.Then a great quake in the Northern Kurils and southern Kamchatka when the tsunami wave reached 25 meters and the whole settlement of Kurilsk was destroyed.Later, in the 1970-80s, it was relatively calm, but already in the 1990s the seismic activity grew again. We see that 20 to 25 years of relative calm is followed by a more active period. I believe we are living in a more active period now, to last about ten years more.But, I could not call such assumptions fully based on science.RT: You’re saying that both you and your colleagues abroad predicted the earthquake in Japan. Why were not enough people evacuated then?ER: A forecast has many parameters. Most important is analysis of seismic activity. Some quakes are constantly recorded and monitored, the information is cataloged. Anomalies, like excessive calmness or excessive activity are analyzed. Further data is used, about the deformation of the lithosphere, thermal and electromagnetic fields.When you have many parameters coinciding, you can announce the forecast. One parameter alone is not enough to predict anything.Several negative factors coincided. First, the Japanese are perhaps best equipped in the world against earthquakes as they are living on a continuous seismic hotbed. They predicted an earthquake, but nobody expected a magnitude 9, which is unique – normally magnitude 8 is forecast. The difference between 8 and 9 is a logarithmic scale. Each digit increment means a ten-time increase of energy.So, nature played a mean joke with them. Before the 11th March quake, a quake on the 9th March in the same zone was considerably weaker – only 7.7, which is still big. But they decided the forecast had been fulfilled and they relaxed. A much stronger quake occurred soon afterward.The tsunami was indeed predicted, but its epicenter was rather close to the shoreline, only 120 km away, whereas the tsunami wave traveled at 400 or even 600 or 800 km/h. So, it obviously reached the shore in ten minutes.Most of the victims resulted not from the earthquake destroying buildings, but from the tsunamis, because the latter were both unexpected and very high. Besides, they hit places that were very vulnerable.RT: What about Russia’s Far East – more earthquakes there? What should be done to reduce the number of casualties in affected areas?ER: As to where are the residents of Russia’s Far Eastern areas supposed to be evacuated? To Moscow? Nobody has left. People will remain living there, regardless of earthquakes.This option has long been refuted, moreover, we don’t know the timing exactly. We know only some probabilities. And we don’t know what its magnitude will be.Petropavlovsk[-Kamchatskiy] is being reinforced now, as part of a special program. Also, our territory, unlike in Japan, is not so densely populated or urbanized. No matter how odd it may sound, earthquakes for us are less dangerous than for Europe or Japan, as they won’t cause extensive destruction or many victims.Well, we had powerful earthquakes in the central part of the Kurils in 2006 and 2007, with tsunamis. Who has noticed them? No-one has died, because nobody lives there. Nothing was destroyed. We should keep our eyes open and not rush to evacuate the residents who live there.Our country is not simple in terms of resettling someone somewhere. Proper homes are necessary, warm clothing etc. How can this be easily done?RT: How will the coastline change?ER: I don’t have relevant data, but I think the landscape will become slightly lower. For instance, during the Shikotan earthquake of 1994 in the southern Kurils. It was a very powerful quake, too, with a magnitude of 8.4.As a result, the Island of Shikotan, sank by 60cm, never to rise. The landscape was changed.It looks like the same may have happened in Japan, but I don’t have direct data now.RT: What else can be affected by the movements of plates in terms of global landscape?ER: Shifts in the plates in such cases may be very significant – affecting large territories. If the shift is about ten meters, the area affected on the surface will be thousands of square kilometers. The shift is very big. Territorially, it’s where the earthquake has happened. Japan may sink a little, while the continental plate rises.RT: How reasonable is it to build nuclear power plants in earthquake zones after such disaster?ER: There is no option. They don’t have energy resources. As for us, we don’t build nuclear power stations in seismic zones. They do.RT: Do you believe in such projects as Glonass to help predict earthquakes more accurately?ER: Such technology is being worked on, but so far it is not available. Our Glonass system inherits most of the features from the GPS. GPS is used, with secondary support from satellites, and the information about the deformations of the surface is recorded. So far though it is hard to use for predictions.RT: Do you work together with your colleagues from abroad to predict such events? Was it the case with Japan?ER: We had a joint Russia-Japan project, but it was rather long ago, in the 1990s. We began to monitor Japan. We managed to detect some precursors then. As head of the center tasked with co-coordinating the work in the country, we are not entitled to forecast earthquakes abroad. We have a lot of work domestically.