Earthquake with magnitude of ML-MEDNET 3.3 on date 21-02-1985 and time 07:24:26 (Italy) in region 4 km W Tortona (AL)

A magnitude ML-MEDNET 3.3 earthquake occured in region: 4 km W Tortona (AL), on

  • 21-02-1985 06:24:26 (UTC)
  • 21-02-1985 07:24:26 (UTC +01:00) Italian time

and geographic coordinates (lat, lon) 44.8990, 8.8100 at 10 km depth.

The earthquake was located by: Bollettino Sismico Italiano INGV.

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
Tortona AL 4 27437 27437
Carbonara Scrivia AL 7 1122 28559
Villaromagnano AL 8 715 29274
Spineto Scrivia AL 8 337 29611
Viguzzolo AL 9 3148 32759
Piovera AL 9 851 33610
Sarezzano AL 9 1171 34781
Sale AL 10 4172 38953
Villalvernia AL 10 955 39908
Paderna AL 11 220 40128
Castelnuovo Scrivia AL 11 5274 45402
Castellar Guidobono AL 11 399 45801
Montecastello AL 11 321 46122
Alluvioni Cambiò AL 11 912 47034
Berzano di Tortona AL 11 157 47191
Cerreto Grue AL 12 323 47514
Rivarone AL 12 381 47895
Pozzolo Formigaro AL 12 4775 52670
Volpeglino AL 12 148 52818
Pietra Marazzi AL 12 904 53722
Pontecurone AL 12 3723 57445
Frugarolo AL 12 1968 59413
Carezzano AL 12 431 59844
Bassignana AL 13 1709 61553
Costa Vescovato AL 13 335 61888
Guazzora AL 13 305 62193
Montegioco AL 13 313 62506
Bosco Marengo AL 14 2457 64963
Casalnoceto AL 14 980 65943
Volpedo AL 14 1227 67170
Monleale AL 14 566 67736
Alzano Scrivia AL 15 377 68113
Castellania AL 15 90 68203
Gavazzana AL 15 180 68383
Pecetto di Valenza AL 15 1267 69650
Gambarana PV 15 225 69875
Isola Sant'Antonio AL 15 717 70592
Casei Gerola PV 15 2500 73092
Sant'Agata Fossili AL 15 425 73517
Cassano Spinola AL 15 1731 75248
Alessandria AL 15 93943 169191
Molino dei Torti AL 15 605 169796
Novi Ligure AL 15 28154 197950
Montemarzino AL 16 341 198291
Suardi PV 16 624 198915
Fresonara AL 16 731 199646
Avolasca AL 16 294 199940
Casal Cermelli AL 16 1234 201174
Basaluzzo AL 17 2087 203261
Rivanazzano Terme PV 17 5312 208573
Pieve del Cairo PV 17 2063 210636
Pasturana AL 17 1318 211954
Casasco AL 17 129 212083
Pozzol Groppo AL 18 328 212411
Sardigliano AL 18 406 212817
Cornale e Bastida PV 18 867 213684
Valenza AL 18 19178 232862
Mezzana Bigli PV 18 1098 233960
Retorbido PV 19 1538 235498
Voghera PV 19 39421 274919
Momperone AL 19 223 275142
Francavilla Bisio AL 19 531 275673
Silvano Pietra PV 19 672 276345
Castellazzo Bormida AL 19 4570 280915
Tassarolo AL 19 672 281587
Frascarolo PV 19 1209 282796
Stazzano AL 20 2486 285282
Godiasco Salice Terme PV 20 3229 288511
Garbagna AL 20 696 289207
Predosa AL 20 2048 291255

Municipalities with at least 50000 inhabitants

An earthquake occurred to
15 Km E of Alessandria (93943 inhabitants)
42 Km SW of Pavia (72576 inhabitants)
47 Km S of Vigevano (63310 inhabitants)
48 Km E of Asti (76202 inhabitants)
55 Km N of Genova (586655 inhabitants)
63 Km S of Novara (104380 inhabitants)
70 Km SW of Milano (1345851 inhabitants)
71 Km NE of Savona (61345 inhabitants)
72 Km W of Piacenza (102191 inhabitants)
72 Km S of Rho (50434 inhabitants)
78 Km S of Legnano (60262 inhabitants)
78 Km SW of Sesto San Giovanni (81608 inhabitants)
80 Km S of Busto Arsizio (83106 inhabitants)
80 Km SW of Cinisello Balsamo (75078 inhabitants)
85 Km SW of Monza (122671 inhabitants)
85 Km S of Gallarate (53343 inhabitants)
89 Km E of Moncalieri (57294 inhabitants)
91 Km E of Torino (890529 inhabitants)
99 Km W of Cremona (71901 inhabitants)
Recent and historical seismicity

These maps show the seismic activity in different time intervals, before the seismic event to which they refer. Data reported in the first two maps come from the analysis carried out in real time by the personnel of the INGV Operating Rooms, immediately after each earthquake. The third map shows data from 1985 to the date of the earthquake: the locations are reviewed by the seismological analysts of the INGV Italian Seismic Bulletin (Bollettino Sismico Italiano dell’INGV). The localization parameters (hypocentral coordinates and magnitude) are the best possible estimate with the data available to the INGV, but are constantly updated according to further data that become available. The location and magnitude parameters, subsequently reviewed by seismological analysts, may vary.

Earthquakes of the 3 days preceding this event

Earthquakes of the 3 days preceding this event

This map shows the earthquake epicenters with magnitude ≥ 0.0, localized with data recorded by the National Seismic Network and other collaborative networks both in Italy and in neighboring countries, in the 72 hours preceding this event. The size of the circle indicates the different classes of magnitude. The colors indicate the different time intervals preceding the seismic event. The black and white star is the epicenter of the current earthquake.
Earthquakes of the 90 days preceding this event

Earthquakes of the 90 days preceding this event

This map shows the earthquake epicenters with magnitude ≥ 2.0, localized with data recorded by the National Seismic Network and other collaborative networks both in Italy and in neighboring countries, in the 90 days preceding this event. The size of the circle indicates the different classes of magnitude. The colors indicate the different time intervals preceding the seismic event. The black and white star is the epicenter of the current earthquake.
Earthquakes from 1985 to the date of the event

Earthquakes from 1985 to the date of the event

This map shows the earthquake epicenters with magnitude ≥ 3.0, localized with data recorded by the National Seismic Network and other collaborative networks both in Italy and in neighboring countries, from 1985 to the date of this event. The size of the circle indicates the different classes of magnitude. The colors indicate the different time intervals preceding the seismic event. The black and white star is the epicenter of the current earthquake.
Earthquakes since 1000 AD until 2019

Earthquakes since 1000 AD until 2019

This map shows the epicenters of the historical earthquakes catalogue CPT15 (Catalogo Parametrico dei Terremoti Italiani, 2015 version 3.0, https://doi.org/10.13127/cpti/cpti15.3) since 1000 AD until 2019. The size of the square indicates the different classes of magnitude. For earthquakes with magnitude ≥ 6.0, it is also shown the year of occurrence and the magnitude value. The black and white star is 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
Felt maps
Locations history
Type Magnitude Date and Time (UTC) Latitude Longitude Depth (km) Published time (UTC) Author Location ID
Bulletin
Rev1000
MLNET 3.3 1985-02-21
06:24:26
44.899 8.81 10 2013-07-15
08:40:51
Bollettino Sismico Italiano INGV 2119
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 1985-02-21 06:24:26 ± 0.312
Latitude 44.8990 ± 0.0210
Longitude 8.8100 ± 0.0301
Depth (km) 10 ± 5 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-VAX
Event type earthquake
Origin ID 2119

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) 3325.6
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 128
Number of associated phases, regardless of their use for origin computation 11
Number of defining phases 11
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.5
Epicentral distance of station closest to the epicenter (degree) 0.00510
Epicentral distance of station farthest from the epicenter (degree) 0.01077
Number of stations at which the event was observed 7
Number of stations from which data was used for origin computation 7
Magnitude information

ML:3.3

Field Value
Value 3.3
Uncertainty
Num. used stations
Type of magnitude ML
Reference to an origin 2119
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2015-04-28 10:37:17
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
--.ENR.Z. 1985-02-21T06:25:06.20 10.0 undecidable manual SN 236 0.0108 1.04 0.2
--.IMP.Z. 1985-02-21T06:25:03.00 10.0 undecidable manual SN 214 0.0106 -1.77 0
--.ORX.Z. 1985-02-21T06:24:58.00 10.0 undecidable manual SG 322 0.0084 -0.19 0.7
--.FIN.Z. 1985-02-21T06:24:53.10 10.0 undecidable manual SG 212 0.0073 -1.13 0.2
--.IMP.Z. 1985-02-21T06:24:49.00 10.0 undecidable manual PN 214 0.0106 0.51 1.3
--.ENR.Z. 1985-02-21T06:24:48.70 10.0 undecidable manual PN 236 0.0108 -0.01 1.7
--.ORX.Z. 1985-02-21T06:24:44.20 10.0 undecidable manual PG 322 0.0084 -0.49 1.5
--.ROB.Z. 1985-02-21T06:24:44.60 10.0 undecidable manual PG 229 0.0080 0.66 1.2
--.FIN.Z. 1985-02-21T06:24:42.70 10.0 undecidable manual PG 212 0.0073 0.29 1.8
--.BVT.Z. 1985-02-21T06:24:42.00 10.0 undecidable manual PG 120 0.0074 -0.76 1.1
--.VEA.Z. 1985-02-21T06:24:38.60 10.0 undecidable manual PG 91 0.0051 0.63 1.3
TDMT - Time Domain Moment Tensor
Fault Plane solutions in the area
Fault Plane solutions

Fault Plane solutions

The map reports the fault plane solutions for earthquakes in the region from 1977 to the date of this event. Red moment tensors are determined using the Regional Centroid Moment Tensor technique (RCMT, http://www.bo.ingv.it/RCMT) applied for earthquakes with magnitude larger than 4.5 in the Euro-Mediterranenan area. Occasionally, when a station azimuthal coverage exists RCMTs can be obtained also for earthquakes with magnitude down to 4.0. The gray moment tensors are obtained with the Time Domain Moment Tensor method (TDMT, http://terremoti.ingv.it/tdmt). This technique is applied to earthquakes with magnitude ML greater than 3.2, when it is possible. The size of symbols 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