How Predictable Are Earthquakes?

‘We should not expect a devastating earthquake in Romania before 2040, with most of them until then reaching no more than 5.7 points on the Richter scale, which presents no major risk.

Corina Cristea, 06.11.2015, 13:36

This statement belongs to honorary
director of the Earth Physics Institute, Gheorghe Marmureanu, who recalled that
Vrancea, the most seismically active area of Romania, produces annually 8 to 12
earthquakes of around 4 points on the Richter scale. According to Gheorghe Marmureanu, Vrancea is unique in the world.

Gheorghe Marmureanu: I looked
at Vrancea, which is a special system, totally different from anything in the
world, even if you could say that the Hindukush in the Himalayas is similar. It
may have strong earthquakes at great depth, but they don’t have the same
manifestation. There is something similar in the north east of Colombia. I
looked at everything that occurred in the last 600 years in Romania. For the
last 300 years of activity I saw what earthquakes caused loss of life and
material goods – in the 312 years I have analyzed there were 5 great
earthquakes that caused loss of life and damage.

A tremor closer to the surface, meaning
less than 100 km, has effects towards Bucharest, Bulgaria and Serbia, they are
tremors directing destructive energy in those directions. Deeper tremors get
directed mostly towards Moldova and Ukraine. There is an alternation of surface
and deep tremors, and by this logic, Marmureanu said that a quake oriented towards
the northwest would occur sometime in 2040, because the one in March 1977 was a
surface tremor. There is the possibility that it will not occur even then,
because in 1986 in Vrancea there was a 6.9 magnitude earthquake that did not do
any damage, but released a lot of energy. The Earth is a living system, in
continuous transformation, says Gheorghe Marmureanu.

Gheorghe Marmureanu: We have the great African rift, developing
day by day. The waters in the Red Sea have already run into the rift. Africa
will one day break up, as it shifts upwards. The south and east of Africa will
dislocate and form another continent with Madagascar. We don’t see it, but
America moves further away from Europe every year by 45 to 55 mm. Everything is
alive. Below us, between 110 to 200 km and 3000 km, there is magma. Magma is
not still, it moves. The upper magma cools, the lower magma is hot, there are
convection currents in some places from left to right, in other places from
right to left. Above the magma are tectonic plates. There are 16 tectonic
plates, and at the places they meet, across their thickness, which is 80 to 100
km, there are non-linear phenomena that cannot be controlled.

Earthquakes have different causes, 98% of them are tectonic and
superficial. The tectonic plates, which have various thickness and sizes,
interact. The greatest tectonic plate is the Pacific one, the Eurasian one,
which runs from the mid-Atlantic to the Barents Sea, next to others such as the
Philippine one, the Pacific plate, the North American plate, and all these
float on magma, a melting substance where earthquakes cannot occur, because for
earthquakes a crystalline structure is needed, as explained by Gheorghe
Marmureanu. Earthquakes need a crystalline structure, a structure that can
store potential energy that it releases later. In Romania, tremors do not occur
because one plate slides against another, it is a system of continental
collision. So how predictable earthquakes really are?

Gheorghe Marmureanu: Earthquakes are earthquakes. If they would
be predictable they would be controllable, which we cannot do in fact. They
occur anywhere and anytime on this earth.

However, Romania has set up a system of real time tremor warning.
Professor Marmureanu said about this system:

Gheorghe Marmureanu: Our system has been granted an award by the
European Community, it is a system that allows for the magnitude of the tremor
to be established in four seconds. If the system reveals a 7-egree tremor, then
all users go on alert, all the areas with a major risk in case of earthquake.
It is the only system in the world, aside from the Japanese one.

In the event of an earthquake, at risk installations get blocked
automatically, and 30 seconds before the earthquake occurs, state institutions
and the Committee for States of Emergency get alerted.