The red marker on the map presents the epicenter of this earthquake, it's origin was in Croatia, at a depth of 10 km, 17 km W-NW of Sisak, 32 km S-SE of Zagreb, the capital of Croatia, and 132 km E-SE of Ljubljana , the capital of Slovenia.
|
Time in origin (GMT) |
Latitude, degree |
Longitude, degree |
Depth, km |
Stations number |
Ms/N |
mb/N |
I0 (calculated) |
GAP |
Center |
1
|
11:19:55.0
|
45.56 |
16.17 |
10.0 |
53
|
6.7/24 |
6.2/27 |
9.5 |
|
GS RAS(Verified) Federal research center, Geophysical survey of Russian Academy of Sciences
|
2
|
11:19:56.5
|
45.76 |
16.5 |
10.0 |
10
|
|
6.2/9 |
8-8.5 |
|
GS RAS(Preliminary) Federal research center, Geophysical survey of Russian Academy of Sciences
|
3
|
11:19:54.6
|
45.46 |
16.31 |
10.0 |
48
|
Mw 6.4 |
|
|
69
|
CSEM European - Mediterranean seismological center
|
4
|
11:19:54.8
|
45.42 |
16.26 |
10.0 |
133
|
Mw 6.4/89 |
6.0/99 |
|
13
|
NEIC National Earthquakes Information Center of US Geological Service
|
Fig. 1 presents fragments of records obtained from digital stations Kasperske Hory (∆ 4º), Malin Array(∆ 10.1º), Keskin Array (∆ 14.1º) , Vasula (∆ 14.4º), Kongsberg (∆ 14.7º). Fig. 2 presents fragments of records obtained from digital stations Obninsk (∆ 16.1º), Pulkovo (∆ 16.6º), Kislovodsk (∆ 18.9º), Khabaz (∆ 19.1º), Belogornoye (∆ 21.6º).
Image 1
Image 2
GS RAS registered two foreshocks, one was 29 hours 51 minutes with М=5.3 before the main shock and another was 28 hours 29 minutes before the main shock with с М=4.7 и четыре афтершока с М>=4 в течении суток.
N |
Time in origin (GMT) |
Latitude, degree |
Longitude, degree |
Depth, km |
Stations number |
Ms/N |
mb/N |
I0 (calculated) |
Region |
20204891
|
28/12/2020 05:28:08.0.0 |
45.44 |
16.14 |
10.0 |
57 |
|
5.3/30 |
6-6.5 |
Northwestern Balkan region
|
20204898
|
28/12/2020 06:49:59.0.0 |
45.57 |
16.17 |
10.0 |
24 |
|
4.7/9 |
4.5-5 |
Northwestern Balkan region
|
20204916
|
29/12/2020 12:00:10.0.0 |
45.52 |
16.16 |
10.0 |
8 |
|
4.0/2 |
3 |
Northwestern Balkan region
|
20204917
|
29/12/2020 12:34:42.0.0 |
45.43 |
16.11 |
10.0 |
24 |
|
4.4/9 |
4 |
Northwestern Balkan region
|
20204929
|
30/12/2020 05:15:04.1.0 |
45.45 |
16.18 |
10.0 |
31 |
|
4.7/11 |
4.5-5 |
Northwestern Balkan region
|
20204930
|
30/12/2020 05:26:42.0.0 |
45.5 |
16.19 |
10.0 |
31 |
|
4.6/14 |
4.5 |
Northwestern Balkan region
|
The focal mechanism solution of the origin was calculated in GS RAS with signs of initial arrivals of P waves at 96 stations, including 65 stations which registered compression waves (plus signs) and 31 stations which registered tensile waves (minus signs). These stations are located in the interval of epicentral distances of 1-93º and in azimuth sector Az=8-353º. The focal mechanism solution in stereographic projection on the lower hemisphere and its elements are presented in the table. The table also contains focal mechanism solutions obtained at the USGS NEIC with WW-phase Moment Tensor (Mww) technique and in Lamont-Dohert Earth Observatory of Columbia University, USA (LDEO GCMT) with СМТ (Centroid moment tensor) technique. Solutions from different centers are close. The earthquake occurred under the action of similar in magnitude compression stresses oriented to the south-southwest (AZ=195º) according to GS RAS and to the north (AZ=357-358º) according to USGS NEIC and LDEO GCMT and tensile stresses oriented to the east (AZ=87-102º). One nodal plane NP1 strikes W-SW (STK=242º) according to GS RAS and SW (STK=223-224º) according to USGS NEIC and LDEO GCMT, another plane NP2 strikes SE (STK=132-146º), both planes are enough steeply dipping to the horizon at close angles (DIP=68-89º). The type of motion along NP1 – left latteral slip, along NP2 – right latteral slip. According to USGS NEIC – Mo=4.411*10**18 N*m, Mwb=6.4, according to LDEO GCMT – Mo=4.64*10**18 N*m, Mw=6.4.
Axes of main strengths |
Nodal planes |
Center |
|
T |
P |
N |
NP1 |
NP2 |
PI: 25
Azm: 102
|
PI: 6
Azm: 195
|
PI: 64
Azm: 297
|
Stk: 242
Dp: 68
Slip: 15
|
Stk: 146
Dp: 76
Slip: 157
|
GS RAS Federal research center, Geophysical survey of Russian Academy of Sciences
|
|
PI: 11
Azm: 90
|
PI: 9
Azm: 358
|
PI: 76
Azm: 228
|
Stk: 224
Dp: 89
Slip: 14
|
Stk: 134
Dp: 76
Slip: 179
|
NEIC National Earthquakes Information Center of US Geological Service
|
|
PI: 11
Azm: 87
|
PI: 0
Azm: 357
|
PI: 79
Azm: 265
|
Stk: 223
Dp: 82
Slip: 8
|
Stk: 132
Dp: 82
Slip: 172
|
GCMT Lamont-Doherty Earth Observatory Global CMT Columbia University, USA
|
|