Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of Md 2.2 on date 18-05-1991 and time 05:11:03 (Italy) in region 2 km NE Castelfiorentino (FI)

A magnitude Md 2.2 earthquake occured in region: 2 km NE Castelfiorentino (FI), on

  • 18-05-1991 03:11:03 (UTC)
  • 18-05-1991 05:11:03 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 43.6240, 10.9890 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.

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Municipalities within 20 km from the epicenter

Distances are determinated based on the geographic coordintes of the (Istat).
Municipality Region Dist Inh Cum Inh
Castelfiorentino FI 2 17504 17504
Montespertoli FI 7 13537 31041
Certaldo FI 9 16121 47162
Gambassi Terme FI 10 4870 52032
Montaione FI 10 3700 55732
Empoli FI 11 48109 103841
Montelupo Fiorentino FI 12 14098 117939
San Miniato PI 13 27934 145873
Capraia e Limite FI 13 7670 153543
San Casciano in Val di Pesa FI 16 17062 170605
Tavarnelle Val di Pesa FI 16 7800 178405
Barberino Val d'Elsa FI 17 4386 182791
Palaia PI 17 4612 187403
Cerreto Guidi FI 18 10870 198273
San Gimignano SI 18 7820 206093
Fucecchio FI 19 23618 229711
Vinci FI 19 14604 244315
Lastra a Signa FI 19 20156 264471
Montopoli in Val d'Arno PI 19 11148 275619
Santa Croce sull'Arno PI 20 14601 290220
Signa FI 20 19179 309399

Municipalities with at least 50000 inhabitants

An earthquake occurred to
22 Km SW of Scandicci (50609 inhabitants)
27 Km SW of Firenze (382808 inhabitants)
30 Km SW of Prato (191150 inhabitants)
35 Km S of Pistoia (90315 inhabitants)
44 Km NW of Siena (53903 inhabitants)
46 Km SE of Lucca (89046 inhabitants)
48 Km E of Pisa (89158 inhabitants)
55 Km E of Livorno (159219 inhabitants)
65 Km E of Viareggio (62467 inhabitants)
74 Km W of Arezzo (99543 inhabitants)
82 Km SE of Massa (69479 inhabitants)
88 Km SE of Carrara (63133 inhabitants)
97 Km N of Grosseto (82087 inhabitants)
100 Km SW of Imola (69797 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
Bulletin
Rev1000 		Md 2.2
M 2.3 		1991-05-18
03:11:03		 43.624 10.989 10 2013-07-15
08:41:04		 Bollettino Sismico Italiano INGV 141399
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 1991-05-18 03:11:03 ± 0.324
Latitude 43.6240 ± 0.0218
Longitude 10.9890 ± 0.0150
Depth (km) 10 (operator assigned)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-VAX
Event type earthquake
Origin ID 141399

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) 2706.1
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 196
Number of associated phases, regardless of their use for origin computation 14
Number of defining phases 14
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.4
Epicentral distance of station closest to the epicenter (degree) 0.00219
Epicentral distance of station farthest from the epicenter (degree) 0.00623
Number of stations at which the event was observed 7
Number of stations from which data was used for origin computation 7
Magnitudes information

Md:2.2

Field Value
Value 2.2
Uncertainty
Num. used stations 3
Type of magnitude Md
Reference to an origin 141399
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2013-01-04 19:12:00

M:2.3

Field Value
Value 2.3
Uncertainty
Num. used stations
Type of magnitude M
Reference to an origin 141399
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2015-04-28 09:35:22
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
--.CRE.Z. 1991-05-18T03:11:27.43 10.0 undecidable manual SG 90 0.6882 -0.03 0.6
--.SFI.Z. 1991-05-18T03:11:26.33 10.0 undecidable manual SG 65 0.6771 -0.63 0.4
--.MME.Z. 1991-05-18T03:11:23.40 10.0 undecidable manual SG 340 0.5994 -1.18 0.2
--.BDI.Z. 1991-05-18T03:11:22.00 10.0 undecidable manual SG 327 0.5217 0.14 0.7
--.MME.Z. 1991-05-18T03:11:17.00 10.0 undecidable manual PG 340 0.5994 1.45 0.2
--.SFI.Z. 1991-05-18T03:11:17.36 10.0 undecidable manual PG 65 0.6771 0.44 1.2
--.CRE.Z. 1991-05-18T03:11:17.58 10.0 undecidable manual PG 90 0.6882 0.38 1.3
--.PTF.Z. 1991-05-18T03:11:16.40 10.0 undecidable manual SG 9 0.333 0.35 0.6
--.PII.Z. 1991-05-18T03:11:15.36 10.0 undecidable manual SG 286 0.3441 -0.99 0.3
--.FIR.Z. 1991-05-18T03:11:13.00 10.0 undecidable manual SG 52 0.2442 0.05 1.1
--.BDI.Z. 1991-05-18T03:11:13.89 10.0 undecidable manual PG 327 0.5217 -0.09 1.7
--.PII.Z. 1991-05-18T03:11:10.73 10.0 positive manual PG 286 0.3441 -0.06 3.6
--.PTF.Z. 1991-05-18T03:11:10.80 10.0 undecidable manual PG 9 0.333 0.18 1.8
--.FIR.Z. 1991-05-18T03:11:07.50 10.0 undecidable manual PG 52 0.2442 -1.33 0.3
TDMT - Time Domain Moment Tensor
Fault Plane solutions in the area
Download
Type Description Link
QuakeML - small Event, Origin, FocalMechanism Download
QuakeML - full Event, Origin, FocalMechanism, Amplitude, Arrival, Pick, Station Magnitude Download