INGVCENTRO​NAZIONALE​TERREMOTI
Sala Sismica

Earthquake with magnitude of mb 4.7 on date 08-03-2018 and time 17:42:37 (Italy) in region Costa Tunisina (TUNISIA)

A magnitude mb 4.7 earthquake occured in region: Costa Tunisina (TUNISIA), on

  • 08-03-2018 16:42:37 (UTC)
  • 08-03-2018 17:42:37 (UTC +01:00) Italian time

and geographic coordinates (lat, lon) 36.94, 10.26 at 20 km depth.

The earthquake was located by: Sala Sismica INGV-Roma.

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

No Italian municipalities within 20 km distance.

Municipalities with at least 50000 inhabitants

No Italian municipalities within 100 km from the epicenter with at least 50000 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.
Significant earthquakes since 1000 AD until 2006

Significant earthquakes since 1000 AD until 2006

This map shows the epicenters of the historical earthquakes catalogue CPT11 (Catalogo Parametrico dei Terremoti Italiani, 2011 version) with estimated magnitude ≥ 5.0 since 1000 AD until 2006. 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

Seismic hazard maps provide probabilistic estimates of the earthquake ground shaking exceeding a given threshold in a given geographic region within a given time window. Thus, it is not a deterministic prediction - a target that may be never reached given the complexity of the earthquake physical phenomenon - nor of the maximum expected earthquake since this has extremely low probabilities to occur.

In 2004, it was published the seismic hazard map of Italy (http://zonesismiche.mi.ingv.it) that provides a picture of the most hazardous geographic regions. The seismic hazard map of Italy (GdL MPS, 2004; rif. Ordinanza PCM del 28 aprile 2006, n. 3519, All. 1b) provides the 10% probability of exceedance in 50 years of the horizontal acceleration at rock sites (i.e., Vs30>800 m/s; cat. A, 3.2.1 of the D.M. 14.09.2005).

The colours indicate the various values of the ground acceleration that have 10% to be exceeded within 50 years. In general, the colours associated to low values of acceleration refer to areas that are less hazardous and stronger earthquakes repeat less frequently although they may still occur.

Seismic hazard map

Seismic hazard map

This map shows the seismic hazard map of Italy for the region where the earthquake occurred.
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 100 mb 4.7
Mwp 4.7
2018-03-08
16:42:37
36.94 10.26 20 2018-03-08
16:55:29
Sala Sismica INGV-Roma 54440501
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2018-03-08 16:42:37
Latitude 36.94
Longitude 10.26
Depth (km) 20 (from location)
Evaluation mode of Origin automatic
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV-A
Event type earthquake
Origin ID 54440501

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 7924
Semi-minor axis of confidence ellipse (meter) 983
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 194
Circular confidence region, given by single value of horizontal uncertainty (meter) 6396.4
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 110.301
Number of associated phases, regardless of their use for origin computation 13
Number of defining phases 13
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 2.38842
Epicentral distance of station closest to the epicenter (degree) 2.44121
Epicentral distance of station farthest from the epicenter (degree) 11.75058
Number of stations at which the event was observed 13
Number of stations from which data was used for origin computation 13
Magnitudes information

Mwp:4.7

Field Value
Value 4.7
Uncertainty 0.1
Num. used stations 2
Type of magnitude Mwp
Reference to an origin 54440501
Agency INGV
Autore Auto added
Time of creation (UTC) 2018-03-08 16:55:29

mb:4.7

Field Value
Value 4.7
Uncertainty 0.3
Num. used stations 9
Type of magnitude mb
Reference to an origin 54440501
Agency INGV
Autore Auto added
Time of creation (UTC) 2018-03-08 16:55:29
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
IU.PAB.BHZ.00 2018-03-08T16:45:25.52 10.0 positive automatic P 287 11.7506 1.84563 0.952381
OE.DAVA.BHZ. 2018-03-08T16:45:07.32 10.0 positive automatic P 359 10.3548 2.63131 0.930233
OE.KBA.BHZ. 2018-03-08T16:45:05.37 10.0 positive automatic P 12 10.3967 0.0861607 0.869565
MN.TUE.BHZ. 2018-03-08T16:44:55.20 10.0 negative automatic P 356 9.5606 1.33203 0.963855
MN.BNI.BHZ. 2018-03-08T16:44:41.85 10.0 positive automatic P 343 8.5518 1.90507 0.91954
IV.MRVN.BHZ. 2018-03-08T16:44:05.48 10.0 negative automatic P 46 6.1876 -1.87952 0.952381
RD.PGF.BHZ. 2018-03-08T16:43:59.18 10.0 positive automatic P 351 5.6954 -1.49976 0.952381
MN.TIP.BHZ. 2018-03-08T16:43:59.07 10.0 negative automatic P 64 5.5875 -0.0723682 0.97561
WM.MAHO.BHZ. 2018-03-08T16:43:57.10 10.0 positive automatic P 304 5.5472 -1.35193 0.952381
MN.CEL.BHZ. 2018-03-08T16:43:49.77 10.0 positive automatic P 72 4.6576 3.4211 0.952381
TT.TATN.BHZ.00 2018-03-08T16:43:41.53 10.0 positive automatic P 177 4.362 -0.731351 0.952381
MN.VSL.BHZ. 2018-03-08T16:43:15.07 10.0 positive automatic P 345 2.6521 -3.64505 0.97561
MN.CLTB.BHZ. 2018-03-08T16:43:13.00 10.0 positive automatic P 74 2.4412 -1.91958 0.909091
TDMT - Time Domain Moment Tensor

TDMT details

Field Value
Magnitude4
Scalar Moment1.25871E+22 dyne-cm
Computed depth18 km
QualityCa
Variance Reduction35.59%
Double Couple91%
CLVD9%
ISO0%
Model usedCIA
Modeautomatic
Statuspreliminary

Moment Tensor Components

Component Value
Mrr1.8757E+21
Mtt9.3477E+21
Mpp-1.12234E+22
Mrt-4.9674E+21
Mrp4.9065E+21
Mtp-1.2195E+21

Nodal Planes

Name Strike Dip Rake
PN13218435
PN222755172

Focal Mechanism

Focal Mechanism

psmeca (GMT documentation)

10.2568 36.9352 18 321 84 35 227 55 172 1.25871 22 10.7568 37.4352

TDMT references

More info and references

Station Distribution

Station Distribution

TDMT station details

Sta Dist Azi V R zcor
CORL 290 67.5 22.04% 129
MBFT 263.7 64 41.63% 123
MMGO 254.3 70.7 23.45% 124
SOLUN 316.8 65.1 48.14% 130
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