Mag 5.5 Earthquake, Romania and Earthquakes in Ionian Sea

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In summary, there were moderate earthquakes in Turkey, in the Mediterranean Sea of Cyprus, in Georgia and in Iran. Some history and insight is available on the USGS website.
  • #1
Astronuc
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I noticed a relatively strong earthquake in SE Europe this weekend.
https://earthquake.usgs.gov/earthquakes/eventpage/us1000hi43/executive
M5.5 - 16km SE of Comandau, Romania
2018-10-28 00:38:11 (UTC)
45.652°N 26.403°E
151.0 km depth - very deep

Then I noticed several earthquakes in the Ionian Sea off the east coast of Greece. Most were between 4 to 5 Mag, but one today was 5.6 Mag.

https://earthquake.usgs.gov/earthquakes/eventpage/us1000hivt/executive
M 5.6 - 40km SW of Mouzaki, Greece
2018-10-30 02:59:58 (UTC)
37.531°N 20.440°E
10.0 km depth

There are moderate earthquakes in Turkey, in the Mediterranean Sea of Cyprus, in Georgia and in Iran.

Wondering if this will lead to a strong earthquake in the region.
 
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  • #2
Astronuc said:
Wondering if this will lead to a strong earthquake in the region.
well there was the M 6.8 event offshore SW Greece last week

that 5.6 you listed above was an aftershock to it

Dave
 
  • #3
davenn said:
well there was the M 6.8 event offshore SW Greece last week

that 5.6 you listed above was an aftershock to it

Dave
Thanks, Dave. I should have checked. I managed to miss it.

https://earthquake.usgs.gov/earthquakes/eventpage/us1000hhb1/executive
M 6.8 - 33km SW of Mouzaki, Greece
2018-10-25 22:54:51 (UTC)
37.506°N 20.563°E
14.0 km depth - shallow

Some history and insight
https://earthquake.usgs.gov/earthquakes/eventpage/us1000hhb1/region-info
 
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  • #4
Regarding that 6.8 in Greece: is this 'normal' to have this many aftershocks, at this range? There was ~ 60 events between 4.2 and 5.6 since the main one, but actually nothing below 4 (according to earthquake.usgs.gov).
 
  • #5
Rive said:
Regarding that 6.8 in Greece: is this 'normal' to have this many aftershocks, at this range? There was ~ 60 events between 4.2 and 5.6 since the main one, but actually nothing below 4 (according to earthquake.usgs.gov).
The USGS does not necessarily report on lower than Mag 4.5 around the world, or below Mag 2.5 in the US. One has to look at the filters or limitations on the data.
https://earthquake.usgs.gov/data/comcat/data-availability.php

One can get more information from https://earthquake.usgs.gov/earthquakes/eventpage/us1000hhb1/executive , and select View Nearby Seismicity

For more details, see http://www.geophysics.geol.uoa.gr/stations/maps/recent.html, a website by the Seismological Laboratory, University of Athens, Greece.
Select at least 10 days (from day of this post) to capture the recent Mag 6.8 on October 25. Notice activity before and after the Mag 6.8 earthquake.

26/10 03:54:54, M: 3.5
26/10 02:36:08, M: 3.9
26/10 02:17:33, M: 4.0
26/10 02:09:32, M: 3.9
26/10 01:46:00, M: 3.6
26/10 01:43:30, M: 3.5
26/10 01:10:45, M: 3.5
26/10 01:05:58, M: 4.5
26/10 00:32:54, M: 4.6
26/10 00:31:41, M: 3.6
26/10 00:23:14, M: 4.4
26/10 00:13:40, M: 4.5
26/10 00:06:27, M: 3.7
25/10 23:37:24, M: 3.9
25/10 23:09:21, M: 5.1
25/10 22:54:50, M: 6.8
25/10 22:52:59, M: 2.7
25/10 22:22:54, M: 4.8
25/10 21:13:30, M: 0.8
25/10 20:12:51, M: 1.8
25/10 18:30:24, M: 1.9
25/10 14:45:35, M: 1.1
25/10 14:38:14, M: 1.3
25/10 11:59:27, M: 1.4
25/10 11:01:19, M: 2.1
25/10 08:15:59, M: 1.3
25/10 08:09:34, M: 2.7
25/10 02:47:40, M: 1.8
25/10 02:10:34, M: 1.9
25/10 01:57:40, M: 1.1
25/10 01:52:28, M: 2.1
25/10 01:43:49, M: 1.0
25/10 01:08:14, M: 1.3

In the case of the US, see https://pnsn.org/ for the Pacific Northwest Seismic Network, and compare their map to the USGS Map for Latest Earthquakes over the same time period, and in the northeast US see http://aqms.ldeo.columbia.edu/recent.html

In the US, there is the Advanced National Seismic System (ANSS)
https://earthquake.usgs.gov/monitoring/anss/

World wide is Global Seismographic Network (GSN)
https://earthquake.usgs.gov/monitoring/gsn/
 
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  • #6
Thanks for the links. The presence of the smaller ones makes it less weird, but still, is it normal to have this mucs aftershocks (with that many 4+ ones)?
 
  • #7
Rive said:
but still, is it normal to have this mucs aftershocks (with that many 4+ ones)?
yup, definitely normal ... A M6.8 is a significant event and it was shallow so there is going to be lots of aftershocks as stresses
in the fault(s) and surrounding area readjust
 
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  • #8
Rive said:
There was ~ 60 events between 4.2 and 5.6 since the main one, but actually nothing below 4 (according to earthquake.usgs.gov).
USGS data doesn't show events below M4.0 ( usually M4.5) outside of the USA
 
  • #9
davenn said:
yup, definitely normal ...
Thanks! So nothing like a new vulcano there, or anything? ......By the way, how would that 'sound' like?
 
  • #10
Rive said:
So nothing like a new vulcano there,

Not likely ... this region is seismically active and the USGS states in its info that there has been 13 events around this magnitude in the surrounding region
of SW Greece and offshore.

Generally the Mediterranean area is a subduction zone with the African Plate going down under the European end of the Eurasian Plate.
This is what causes the well known volcanic activity in the region ... Mt Vesuvius, Thera Caldera ( Santorini Islands), Stromboli, Mt Etna,
to name a few.
Rive said:
...By the way, how would that 'sound' like?

what sound ? the earthquake ?
I have experienced a number of quakes above M6.0 back when I used to live in southern New Zealand. Sometimes there's a
rumbling - roaring sound even before the shaking starts. Other times the sound is during the shaking.
This is noise from the ground, not the creaking of the building etc.Dave
 
  • #11
Sorry for the confusion: I meant, if there is a specific pattern in the amount/frequency/strength/depth of earthquakes if the reason is a new vulcano.
 
  • #12
Are you thinking of the infamous 'harmonic tremor' as magma rises in chimney ??
Be Not There !

FWIW, a friend passed on an interesting observation about geology students: Budding volcanologists and seismologists *always* park facing the exit...
 
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  • #13
Nik_2213 said:
'harmonic tremor'
That just gave me the right direction for a search, thanks!

Nik_2213 said:
FWIW, a friend passed on an interesting observation about geology students: Budding volcanologists and seismologists *always* park facing the exit...
I was told once that the ratio of hypochonders in the first years any medical university will be ~ 110%: for the few who is not worrying about their health there are always more with self-suspected multiple personalities...
 
  • #14
Rive said:
Sorry for the confusion: I meant, if there is a specific pattern in the amount/frequency/strength/depth of earthquakes if the reason is a new vulcano.

Nik_2213 said:
'harmonic tremor'
Volcanic harmonic tremor produces quite a unique record on a seismogram as there is no identifiable P, S or surface waves.
Rather there is just a continuous vibration with not a lot of variation in amplitude that can last minutes or hours ...

An example ...

http://earthquake-report.com/wp-content/uploads/2012/07/RETU_SHZ_EC_-.2012072900.gifDave
 
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1. What is a Mag 5.5 earthquake?

A Mag 5.5 earthquake refers to the magnitude of an earthquake, which is a measure of the energy released during the seismic event. It is a logarithmic scale, meaning that a magnitude 5 earthquake is 10 times stronger than a magnitude 4 earthquake.

2. Where is Romania?

Romania is a country located in southeastern Europe, bordering the Black Sea. It is situated in the Balkan Peninsula and shares borders with Bulgaria, Serbia, Hungary, Ukraine, and Moldova.

3. Why do earthquakes occur in Romania?

Romania is located in a seismically active area, known as the Vrancea seismic zone, where multiple tectonic plates converge. This makes the region prone to earthquakes, with the most powerful ones occurring at the depth of the earth's crust in the Vrancea Mountains.

4. How do scientists predict earthquakes?

Currently, there is no reliable way to predict earthquakes. However, scientists use seismometers and other instruments to monitor seismic activity and identify patterns that may indicate the likelihood of an earthquake in a certain area. These predictions are not precise and are only used as a warning for people to take necessary precautions.

5. Are earthquakes in the Ionian Sea a common occurrence?

Earthquakes in the Ionian Sea are relatively common due to the region's location on a major fault line where the Eurasian and African plates meet. However, not all earthquakes are felt on land as they may occur at greater depths or in remote areas. The frequency and intensity of earthquakes in the Ionian Sea vary, with some causing significant damage and others going unnoticed.

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