Felt earthquake in the Little Carpathians Mts. source zone (March 5th, 2012) and related seismic activity in the area AIM third annual meeting October 10-13, 2012 Smolenice castle Miriam Kristeková 1, Lucia Fojtíková 1, Andrej Cipciar 1, Juraj Sekereš 2, Dagmar Sekerešová 2, Progseis, Ltd. Kristián Csicsay 1, Erik Bystrický 1 1 Geophysical Institute SAS, Bratislava, Slovakia 2 Progseis, Ltd., Trnava, Slovakia

felt earthquake (Ml=3.1) in the Little Carpathians Mts. source zone on March, 5th 22:56 UTC basic information about this eartquake paradox in response of the public to this EQ instalations of temporary stations related seismic activity in the area results of the first analyses our plans what to do next Outline

EQ parameters (manual processing): - 22:56:57.1 UTC, 48.55N 17.12E, h =14 km, Ml = 3.1 / Progseis - 22:56:59.4 UTC, 48.55N 17.16E, h = 5 km, Ml = 2.9 / GFÚ SAV Local earthquake, March, 5 th 2012: SMOL, D = 18 km ZST, D = 40 km

EQ parameters (manual processing): - 22:56:57.1 UTC, 48.55N 17.12E, h =14 km, Ml = 3.1 / Progseis - 22:56:59.4 UTC, 48.55N 17.16E, h = 5 km, Ml = 2.9 / GFÚ SAV Local earthquake, March, 5 th 2012: MODS March,5th 2012

EQ parameters (manual processing): - 22:56:57.1 UTC, 48.55N 17.12E, h =14km, Ml = 3.1 / Progseis - 22:56:59.4 UTC, 48.55N 17.16E, h = 5km, Ml = 2.9 / GFÚ SAV Local earthquake, March, 5 th 2012: Local seismic network Progseis National network of seismic stations GFÚ SAV Seismic stations built in cooperation (GFÚ SAV, USHM AV CR, Progseis)

Earthquake epicenter by various agencies LAKS PLAV (automatic location) (manual location)

The first 24 hours (March, 6 th 2012) People in the villages nearby frightened and anxious (according journalists), receiving a lot of attention in the news in TV and in the press Questions whether the felt event was an earthquake or explosion in nearby military area Almost constantly ringing phones from reporters asking for information and interviews about the event (Ml=3 only!) Data preliminary processing, reprocessing with new available data,... Preparations for the field campaign next day Public and media response to the earthquake – the paradox

The first 24 hours (March, 6 th 2012) -announcement with the basic earthquake parameters was prepared and issued in the morning published on our web page and sent to the press agencies and to the well known media (TV, press) containing also the message asking people who felt earthquake to fill in our macroseismic questionnaire - press conference in the afternoon unusually weak response of the public to macroseismic survey Public and media response to the earthquake – the paradox

6 persons in the field (incl. 1 student) - meeting at the headquarters of the Military Area explanation of the situation need to obtain permission to enter into this area then - meeting with the major of the nearest village Studienka together with head of the Military Area and his team together with them discussion of possible sites for seismic stations (fulfilling our criteria for selection) few sites were preliminary selected Day after - Field measurements

After selection of the first site our team was splitted into the 2 groups: - the first one to have a look at the remaining sites to make final selection - the second one started to install stations at the first site - > at the end of the day: 2 single stations 1 small array (4 stations: 1 3C, 3 vertical) were succesfully installed Day after - Field measurements

LAKS PLAV temporary stations Day after - Field measurements

Suitable tool to identify aftershocks: Software Nanoseismic Suite (prof. Joswig’s team, Stuttgart) 3/04/ :32 UTC

Day after - Field measurements Suitable tool to identify aftershocks: Software Nanoseismic Suite (prof. Joswig’s team, Stuttgart)

Day after - Field measurements Suitable tool to identify aftershocks: Software Nanoseismic Suite (prof. Joswig’s team, Stuttgart)

Little Carpathians, Mts. – active seismic zone in Slovakia major known earthquake : 1906 M = 5.7, I 0 = VIII-IX EMS98 (Dobra Voda area) subarea of the felt earthquake-> SW from Dobra Voda From historical data: earthquake in 1890, M = , M = , M = , M = 4.7 previous felt earthquakes 1991 M = 2.6, M = 2.9 Related seismic activity in the area

Recent seismic activity - development in time (6/2010 – 6/2012, 83 eartquakes) Related seismic activity in the area 03/ /2011

Recent seismic activity - development in time (6/2010 – 6/2012, 83 earthquakes) normalized energy released per month Related seismic activity in the area 03/ /2011

Recent seismic activity - development in time (6/2010 – 6/2012, 83 earthquakes) Related seismic activity in the area 03/ /2011

Recent seismic activity - map view (6/2010 – 6/2012, 83 earthquakes) Related seismic activity in the area 03/ /2011

we plan to use also another method for the main event and to compute focal mechanisms for more events from this area Focal mechanism of the main shock FOCMEC 5/03/ :56:57.1, Ml = 3.1 MTSTI 21/10/ :58:39.8, Ml = 2.4 Zuzana Jechumtalova (personal comm.):

Macroseismic survey - results Several reports damages Indications that macroseismic effects could be stronger in direction to the north local effect? 32 observations

We have presented preliminary results only and we have a lot to do: - calculate focal mechanisms for more events - relocate related events using relative location technique to identify active faults - investigate possible local effect (noise measurements) -improve our field equipment Conclusions

Thank you for your attention