INGVCENTRO​NAZIONALE​TERREMOTI
Sala Sismica

Earthquake with magnitude of Mw 4.9 on date 26-12-2018 and time 03:19:14 (Italy) in region 4 km NE Viagrande (CT)

A magnitude Mw 4.9 earthquake occured in region: 4 km NE Viagrande (CT), on

  • 26-12-2018 02:19:14 (UTC)
  • 26-12-2018 03:19:14 (UTC +01:00) Italian time

and geographic coordinates (lat, lon) 37.64, 15.12 at -0 km depth.

The earthquake was located by: Gruppo Analisi Dati Sismici, Osservatorio Etneo.

Search earthquakes: Any within 30 km radius

The values of hypocentral coordinates and magnitude may be revised at a later time as more information becomes available.

Municipalities within 20 km from the epicenter

Distances are determinated based on the geographic coordintes of the (Istat).
Municipality Region Dist Inh Cum Inh
Viagrande CT 4 8563 8563
Aci Sant'Antonio CT 4 17984 26547
Trecastagni CT 4 10910 37457
Aci Bonaccorsi CT 5 3524 40981
Aci Catena CT 5 29851 70832
Santa Venerina CT 5 8592 79424
Acireale CT 6 52622 132046
Pedara CT 6 14102 146148
Zafferana Etnea CT 6 9517 155665
Valverde CT 7 7840 163505
San Giovanni la Punta CT 8 23060 186565
Nicolosi CT 8 7463 194028
Tremestieri Etneo CT 8 20589 214617
San Gregorio di Catania CT 9 11966 226583
Milo CT 9 1087 227670
Mascalucia CT 10 31958 259628
Sant'Agata li Battiati CT 10 9479 269107
Aci Castello CT 10 18723 287830
Gravina di Catania CT 10 25838 313668
San Pietro Clarenza CT 11 7743 321411
Giarre CT 11 27659 349070
Sant'Alfio CT 12 1582 350652
Riposto CT 13 14838 365490
Camporotondo Etneo CT 13 5023 370513
Belpasso CT 14 28108 398621
Mascali CT 15 14282 412903
Ragalna CT 16 3924 416827
Catania CT 16 314555 731382
Misterbianco CT 17 49410 780792
Fiumefreddo di Sicilia CT 19 9623 790415
Piedimonte Etneo CT 19 3963 794378
Motta Sant'Anastasia CT 19 12116 806494

Municipalities with at least 50000 inhabitants

An earthquake occurred to
6 Km NW of Acireale (52622 inhabitants)
16 Km N of Catania (314555 inhabitants)
67 Km N of Siracusa (122291 inhabitants)
70 Km SW of Reggio di Calabria (183035 inhabitants)
72 Km SW of Messina (238439 inhabitants)
87 Km NE of Ragusa (73313 inhabitants)
93 Km NE of Vittoria (63339 inhabitants)
93 Km NE of Modica (54633 inhabitants)
94 Km E of Caltanissetta (63360 inhabitants)
100 Km NE of Gela (75827 inhabitants)
Recent and historical Seismicity

These maps show the seismicity for different time windows. The earthquake locations reported in these maps are determined in quasi real-time by the personnel on duty in the seismic surveillance center of INGV in Rome. Note that the earthquake source parameters (hypocentral location and magnitude) are the best estimates obstained with the available data and they are adjourned as additional data become available. The source parameters obtained by the personnel on duty are then revised by the group in charge of the INGV Seismic Bulletin (Bollettino Sismico Italiano dell’INGV).

Earthquakes of the last three days (72 hours)

Earthquakes of the last three days (72 hours) *

This map reports the earthquake epicenters located in the past 72 hours (3 days) from the time this page has been generated. The radius of the circle representing the earthquake on the map scales with magnitude. The color depends on the time of occurrence of the earthquakes with respect to the time of generation of the map (red = 1 hour; orange = 24 hours; yellow = 72 hours). The open star shows the epicenter of the current earthquake.
Earthquakes of the last 90 days

Earthquakes of the last 90 days *

This map reports the Magnitudo ≥ 1.0 earthquake epicenters located using the data acquired by the Italian National Seismic Network and by other collaborating networks in Italy and in the neighbouring countries. The radii of the circles representing the epicenters on the map scale with magnitude. The color of each circle depends on the time of occurrence of the earthquakes with respect to the time of generation of the map (red = 1 hour; orange = 24 hours; yellow = 72 hours; blue = all other earthquakes). The open star shows the epicenter of the current earthquake.
Earthquakes since 1985

Earthquakes since 1985 *

This map reports the Magnitudo ≥ 2.5 earthquake epicenters located using the data acquired by the Italian National Seismic Network and by other collaborating networks in Italy and in the neighbouring countries. The radii of the circles representing the epicenters on the map scale with magnitude. The color of each circle depends on the time of occurrence of the earthquakes with respect to the time of generation of the map (red = 1 hour; orange = 24 hours; yellow = 72 hours; blue = all other earthquakes). The open star shows the epicenter of the current earthquake.
Earthquakes since 1000 AD until 2014

Earthquakes since 1000 AD until 2014 *

This map shows the epicenters of the historical earthquakes catalogue CPT15 (Catalogo Parametrico dei Terremoti Italiani, 2015 version https://emidius.mi.ingv.it/CPTI15-DBMI15/) with estimated magnitude ≥ 5.0 since 1000 AD until 2014. The epicenters are represented by squares which sides scale with the estimated earthquake magnitude. For earthquakes with magnitude ≥ 6.0, it is also shown the year of occurrence and the magnitude value. The open star shows the epicenter of the current earthquake.
Seismic hazard
Shakemap

These three maps show the results of the analysis using the software ShakeMap designed to provide the level of ground shaking experienced in a region using the data recorded by seismometers and strong motion instruments and seismological information regarding the attenuation of the wavefield with distance and the site characteristics. The Shakemaps are determined for research purposes to provide fast estimates of the level of ground shaking produced by the earthquake. The maps are calculated automatically and adjourned progressively as more data become available. See http://shakemap.rm.ingv.it/ for additional information.

The red star indicates the epicenter. The red triangles show the stations of the INGV Italian National Seismic Network and the blue triangles those of the Nationa Accelerometric Network of the Dipartimento della Protezione Civile.

Intensity Shakemap

Intensity Shakemap *

This map shows the distribution of the istrumentally derived intensities. To this purpose, it is used a conversion relation between ground acceleration and velocity, and the Mercalli Modificata (MMI - Modified Mercalli Intensity) scale. In general, the Mercalli intensity scale relies on the effects that the ground shaking produces as reported by an observer.
Peak ground acceleration Shakemap

Peak ground acceleration Shakemap *

This map shows This map shows the distribution of peak ground acceleration expressed as per cent of the acceleration of gravity (i.e., g = 9.81 m/s²).
Peak velocity Shakemap

Peak velocity Shakemap *

This map shows the distribution of peak ground velocities expressed in cm/s.
Felt maps
The earthquake effects in MCS scale as obtained from the compiled questionnaire

The earthquake effects in MCS scale as obtained from the compiled questionnaire *

This map shows the distribution of the effects of the earthquake on the territory in terms of the MCS (Mercalli-Cancani-Sieberg) intensity scale. The intensities are determined using the data provided in the questionnaire (http://www.haisentitoilterremoto.it/) that are analysed using robust statistical techniques since they are not verified individually. Specifically, the assignment of MCS intensities greater or equal the VI degree of the MCS scale require opportune in situ verification by professional experts. The purple start shows the epicenter. This map is prepared every so often that the population fill in new questionnaires. The number of questionnaires used to determine the map and the date and time of the last adjournment are shown in the upper right part of the panel.
Locations history
Type Magnitude Date and Time (UTC) Latitude Longitude Depth (km) Published time (UTC) Author Location ID
Rev 200 ML 4.8 2018-12-26
02:19:14
37.64 15.12 -0 2019-01-31
13:49:09
Gruppo Analisi Dati Sismici, Osservatorio Etneo 64733411
Rev 501 Mw 4.9 2018-12-26
02:19:14
37.63 15.1 3 2018-12-26
08:50:05
TDMT-INGV Revised 64237231
Rev 200 ML 4.8 2018-12-26
02:19:14
37.63 15.1 1 2018-12-26
02:34:02
Sala Operativa INGV-OE (Catania) 64229911
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2018-12-26 02:19:14
Latitude 37.64
Longitude 15.12
Depth (km) 0 ± 0 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 200 -> BULLETIN-OE
Event type earthquake
Origin ID 64733411

Uncertainty

Field Value
Preferred uncertainty description horizontal uncertainty
Semi-major axis of confidence ellipse (meter)
Semi-minor axis of confidence ellipse (meter)
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi)
Circular confidence region, given by single value of horizontal uncertainty (meter) 100
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 88
Number of associated phases, regardless of their use for origin computation 1
Number of defining phases 1
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.27
Epicentral distance of station closest to the epicenter (degree)
Epicentral distance of station farthest from the epicenter (degree)
Number of stations at which the event was observed 0
Number of stations from which data was used for origin computation 0
Magnitudes information

Mw:4.9

Field Value
Value 4.9
Uncertainty
Num. used stations
Type of magnitude Mw
Reference to an origin 64237231
Agency INGV
Autore TDMT-INGV Revised
Time of creation (UTC) 2018-12-26 08:50:05

ML:4.8

Field Value
Value 4.8
Uncertainty 0.2
Num. used stations
Type of magnitude ML
Reference to an origin 64229911
Agency INGV
Autore Sala Operativa INGV-OE (Catania)
Time of creation (UTC) 2018-12-26 02:34:02

ML:4.8

Field Value
Value 4.8
Uncertainty 0.2
Num. used stations
Type of magnitude ML
Reference to an origin 64733411
Agency INGV
Autore Sala Operativa INGV-OE (Catania)
Time of creation (UTC) 2019-01-17 14:39:40
TDMT - Time Domain Moment Tensor

TDMT details

Field Value
Magnitude4.9
Scalar Moment2.76774E+23 dyne-cm
Computed depth3 km
QualityBa
Variance Reduction32.88%
Double Couple98%
CLVD2%
ISO0%
Model usedCIA
Modemanual
Statusreviewed

Moment Tensor Components

Component Value
Mrr-1.13909E+22
Mtt-2.351043E+23
Mpp2.464951E+23
Mrt9.02496E+22
Mrp-5.40268E+22
Mtp-8.6414E+22

Nodal Planes

Name Strike Dip Rake
PN130688-158
PN221568-3

Focal Mechanism

Focal Mechanism

psmeca (GMT documentation)

15.102 37.625 3 306 88 -158 215 68 -3 2.76774 23 15.602 38.125

TDMT references

More info and references

Station Distribution

Station Distribution

TDMT station details

Sta Dist Azi V R zcor
IST3 130.8 4.9 20.67% 108
TDS 250.2 25.1 50.26% 118
MSRU 79.4 26.6 37.19% 102
CAR1 205.1 27.8 37.25% 114
PIPA 254.8 35.4 50.96% 121
TIP 225.2 39.5 61.02% 118
HAGA 38 172.9 36.98% 97
SSY 51.9 182.8 20.7% 99
CROCE 101.3 210 22.59% 104
MUCR 50.6 336.7 31.28% 100
MTTG 67.3 51.3 34.69% 104
HLNI 36.8 213.6 31.66% 99
CEL 99.1 44.4 51.66% 106
PLAC 148.8 51.6 31.13% 113
CSLB 98.3 291 32.39% 109
Focal Mechanism in the area
Focal Mechanisms

Focal Mechanisms *

This map reports the focal mechanisms since 1977 in the region. The white and red beach ball symbols are mechanisms determined using the Regional Centroid Moment Tensor (RCMT, http://www.bo.ingv.it/RCMT) and are determined for earthquakes with magnitude larger than 4.5 in the Euro-Mediterranenan area. Occasionally, when there is a good source-receiver geometry of the target earthquake, the RCMT can be obtained also for earthquakes with magnitude larger than 4.0. The blue and white beach ball symbols indicate the mechanisms obtained from application of the Time Domain Moment Tensor (TDMT, http://cnt.rm.ingv.it/tdmt.html). This technique is used for M ≥ 3.5. The size of the beach ball sysmbol scales with the calculated moment magnitude, Mw.
Download
Type Description Link
QuakeML - small Event, Origin, FocalMechanism Download
QuakeML - full Event, Origin, FocalMechanism, Amplitude, Arrival, Pick, Station Magnitude Download
Waveforms Seismic signals in full SEED format Download