Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of Md 3.7 on date 23-07-1991 and time 10:40:46 (Italy) in region 2 km W Posta (RI)

A magnitude Md 3.7 earthquake occured in region: 2 km W Posta (RI), on

  • 23-07-1991 08:40:46 (UTC)
  • 23-07-1991 10:40:46 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 42.52, 13.08 at 4 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.

Hai sentito il terremoto? Clicca qui

Did you feel it? Fill in the questionnaire.

Municipalities within 20 km from the epicenter

Distances are determinated based on the geographic coordintes of the (Istat).
Municipality Region Dist Inh Cum Inh
Posta RI 2 694 694
Borbona RI 4 617 1311
Micigliano RI 8 127 1438
Leonessa RI 11 2435 3873
Antrodoco RI 11 2588 6461
Borgo Velino RI 13 972 7433
Cittareale RI 13 482 7915
Cagnano Amiterno AQ 14 1369 9284
Montereale AQ 14 2581 11865
Castel Sant'Angelo RI 14 1308 13173
Cantalice RI 15 2755 15928
Poggio Bustone RI 16 2055 17983
Cittaducale RI 18 6828 24811
Barete AQ 18 737 25548
Capitignano AQ 18 665 26213
Monteleone di Spoleto PG 18 599 26812
Rivodutri RI 18 1253 28065
Pizzoli AQ 20 4326 32391

Municipalities with at least 50000 inhabitants

An earthquake occurred to
32 Km NW of L'Aquila (69753 inhabitants)
36 Km E of Terni (111501 inhabitants)
54 Km W of Teramo (54892 inhabitants)
58 Km SE of Foligno (57155 inhabitants)
64 Km NE of Guidonia Montecelio (88673 inhabitants)
66 Km NE of Tivoli (56533 inhabitants)
81 Km E of Viterbo (67173 inhabitants)
85 Km NE of Roma (2864731 inhabitants)
87 Km SE of Perugia (166134 inhabitants)
88 Km W of Montesilvano (53738 inhabitants)
91 Km W of Chieti (51815 inhabitants)
93 Km W of Pescara (121014 inhabitants)
96 Km N of Velletri (53303 inhabitants)
Recent and historical Seismicity
Seismic hazard
Shakemap
Felt maps
Locations history
Type Magnitude Date and Time (UTC) Latitude Longitude Depth (km) Published time (UTC) Author Location ID
Rev 1000 Md 3.7
ML-VAX 3.7 		1991-07-23
08:40:46		 42.52 13.08 4 2013-07-15
08:40:51		 Bollettino Sismico Italiano INGV 146029
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 1991-07-23 08:40:46 ± 0.294
Latitude 42.52 ± 0.01
Longitude 13.08 ± 0.02
Depth (km) 4 ± 2 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-VAX
Event type earthquake
Origin ID 146029

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) 1765.2
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 61
Number of associated phases, regardless of their use for origin computation 59
Number of defining phases 59
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.7
Epicentral distance of station closest to the epicenter (degree) 0.00259
Epicentral distance of station farthest from the epicenter (degree) 0.05585
Number of stations at which the event was observed 41
Number of stations from which data was used for origin computation 41
Magnitudes information

Md:3.7

Field Value
Value 3.7
Uncertainty
Num. used stations 8
Type of magnitude Md
Reference to an origin 146029
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2013-01-04 19:16:19

ML:3.7

Field Value
Value 3.7
Uncertainty
Num. used stations 2
Type of magnitude ML
Reference to an origin 146029
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2015-04-28 13:07:13
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
--.KBA.Z. 1991-07-23T08:42:48.50 10.0 undecidable manual SN 2 0.041 1.35 0.3
--.FVI.Z. 1991-07-23T08:42:34.50 10.0 undecidable manual SN 357 0.0367 -1.18 0.2
--.PTJ.Z. 1991-07-23T08:42:32.00 10.0 undecidable manual SN 30 0.0357 -1.13 0.3
--.LJU.Z. 1991-07-23T08:42:27.00 10.0 undecidable manual SN 16 0.033 0.99 0.4
--.VKA.Z. 1991-07-23T08:42:19.40 10.0 undecidable manual PN 20 0.0555 1 0.7
--.SKO.Z. 1991-07-23T08:42:18.00 10.0 undecidable manual PN 92 0.0559 -0.81 0.7
--.TRI.Z. 1991-07-23T08:42:14.50 10.0 undecidable manual SN 8 0.029 -0.91 0.3
--.RIY.Z. 1991-07-23T08:42:08.50 10.0 undecidable manual SN 18 0.0267 -0.92 0.5
--.BNI.Z. 1991-07-23T08:42:06.00 10.0 undecidable manual PN 301 0.0474 0.09 1.3
--.BHG.Z. 1991-07-23T08:42:06.30 10.0 positive manual PN 358 0.0468 1.27 1.1
--.VDL.Z. 1991-07-23T08:42:00.20 10.0 undecidable manual PN 328 0.0425 1.69 0.3
--.OSS.Z. 1991-07-23T08:41:59.20 10.0 undecidable manual PN 334 0.0419 1.6 0.3
--.TMA.Z. 1991-07-23T08:41:58.00 10.0 undecidable manual PN 321 0.0421 0.13 1.4
--.KBA.Z. 1991-07-23T08:41:57.00 10.0 positive manual PN 2 0.041 0.77 2.1
--.DOI.Z. 1991-07-23T08:41:57.00 10.0 undecidable manual PN 297 0.042 -0.74 0.9
--.BDI.Z. 1991-07-23T08:41:55.50 10.0 undecidable manual SN 311 0.0214 0.31 0.7
--.FVI.Z. 1991-07-23T08:41:49.59 10.0 undecidable manual PN 357 0.0367 -0.02 1.5
--.ZAG.Z. 1991-07-23T08:41:49.20 10.0 undecidable manual PN 31 0.0352 1.87 0.2
--.PTJ.Z. 1991-07-23T08:41:48.50 10.0 undecidable manual PN 30 0.0357 0.36 1.5
--.CKI.Z. 1991-07-23T08:41:48.50 10.0 undecidable manual PN 300 0.0357 0.43 1.4
--.LJU.Z. 1991-07-23T08:41:43.20 10.0 undecidable manual PN 16 0.033 -0.83 0.9
--.SAL.Z. 1991-07-23T08:41:43.00 10.0 undecidable manual PN 330 0.0323 0.08 1.6
--.BOB.Z. 1991-07-23T08:41:41.00 10.0 undecidable manual PN 312 0.0311 -0.08 1.6
--.PGD.Z. 1991-07-23T08:41:38.18 10.0 undecidable manual SN 324 0.0151 -0.45 0.6
--.SFI.Z. 1991-07-23T08:41:37.26 10.0 undecidable manual SN 327 0.0148 -0.69 0.5
--.TRI.Z. 1991-07-23T08:41:37.21 10.0 undecidable manual PN 8 0.029 -0.69 1.1
--.RIY.Z. 1991-07-23T08:41:33.40 10.0 undecidable manual PN 18 0.0267 -1.05 0.7
--.RSM.Z. 1991-07-23T08:41:33.34 10.0 undecidable manual SN 342 0.0133 -0.61 0.6
--.RFI.Z. 1991-07-23T08:41:32.55 10.0 undecidable manual SN 150 0.0125 0.79 0.5
--.PF9.Z. 1991-07-23T08:41:32.50 10.0 undecidable manual PN 134 0.0255 -0.05 1.8
--.MAO.Z. 1991-07-23T08:41:31.70 10.0 undecidable manual SN 266 0.0128 -0.86 0.5
--.CRE.Z. 1991-07-23T08:41:31.67 10.0 undecidable manual SN 323 0.0123 0.27 0.8
--.SGO.Z. 1991-07-23T08:41:28.00 10.0 undecidable manual PN 139 0.0231 -0.91 1.1
--.MME.Z. 1991-07-23T08:41:27.00 10.0 undecidable manual PN 315 0.0216 0.34 1.9
--.BDI.Z. 1991-07-23T08:41:26.63 10.0 undecidable manual PN 311 0.0214 0.4 1.8
--.MS1.Z. 1991-07-23T08:41:26.00 10.0 undecidable manual PN 110 0.0204 1.2 0.8
--.PII.Z. 1991-07-23T08:41:23.50 10.0 undecidable manual PN 303 0.0199 -0.57 1.5
--.PTF.Z. 1991-07-23T08:41:23.40 10.0 undecidable manual PN 315 0.0185 1.59 0.5
--.SEI.Z. 1991-07-23T08:41:22.20 10.0 undecidable manual PN 321 0.0178 1.38 0.7
--.SDI.Z. 1991-07-23T08:41:21.12 10.0 undecidable manual SG 146 0.0087 0.21 0.7
--.ARV.Z. 1991-07-23T08:41:20.76 10.0 undecidable manual SG 354 0.0088 -0.53 0.6
--.VMG.Z. 1991-07-23T08:41:19.60 10.0 undecidable manual PN 322 0.0164 0.92 1.2
--.PGD.Z. 1991-07-23T08:41:16.17 10.0 undecidable manual PN 324 0.0151 -0.5 1.5
--.MSC.Z. 1991-07-23T08:41:15.20 10.0 undecidable manual PN 153 0.0133 1.23 0.8
--.SFI.Z. 1991-07-23T08:41:15.81 10.0 undecidable manual PN 327 0.0148 -0.46 1.6
--.RFI.Z. 1991-07-23T08:41:13.20 10.0 undecidable manual PN 150 0.0125 0.31 1.8
--.SGG.Z. 1991-07-23T08:41:13.90 10.0 undecidable manual PN 139 0.0134 -0.13 1.9
--.RSM.Z. 1991-07-23T08:41:12.93 10.0 undecidable manual PN 342 0.0133 -1.04 0.8
--.MAO.Z. 1991-07-23T08:41:12.61 10.0 undecidable manual PN 266 0.0128 -0.55 1.5
--.CRE.Z. 1991-07-23T08:41:12.82 10.0 undecidable manual PN 323 0.0123 0.32 1.9
--.ASS.Z. 1991-07-23T08:41:08.50 10.0 undecidable manual SG 330 0.0056 -1.33 0.2
--.SDI.Z. 1991-07-23T08:41:05.10 10.0 undecidable manual PG 146 0.0087 -1.34 0.6
--.ARV.Z. 1991-07-23T08:41:05.96 10.0 undecidable manual PG 354 0.0088 -0.7 1.2
--.CP9.Z. 1991-07-23T08:41:00.00 10.0 undecidable manual PG 188 0.0059 -0.69 1.4
--.MNS.Z. 1991-07-23T08:40:59.50 10.0 undecidable manual SG 245 0.0028 0.29 0.7
--.ASS.Z. 1991-07-23T08:40:58.72 10.0 undecidable manual PG 330 0.0056 -1.32 0.5
--.AQU.Z. 1991-07-23T08:40:57.88 10.0 undecidable manual SG 124 0.0026 0 0.8
--.MNS.Z. 1991-07-23T08:40:53.94 10.0 undecidable manual PG 245 0.0028 0.03 1.9
--.AQU.Z. 1991-07-23T08:40:53.00 10.0 undecidable manual PG 124 0.0026 -0.14 1.9
TDMT - Time Domain Moment Tensor
Focal Mechanism in the area
Download
Type Description Link
QuakeML - small Event, Origin, FocalMechanism Download
QuakeML - full Event, Origin, FocalMechanism, Amplitude, Arrival, Pick, Station Magnitude Download