Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of Md 2.5 on date 20-07-1991 and time 01:42:44 (Italy) in region 4 km SE San Miniato (PI)

A magnitude Md 2.5 earthquake occured in region: 4 km SE San Miniato (PI), on

  • 19-07-1991 23:42:44 (UTC)
  • 20-07-1991 01:42:44 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 43.6520, 10.8760 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.

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
San Miniato PI 4 27934 27934
Castelfiorentino FI 9 17504 45438
Montopoli in Val d'Arno PI 9 11148 56586
Empoli FI 10 48109 104695
Palaia PI 10 4612 109307
Fucecchio FI 10 23618 132925
Santa Croce sull'Arno PI 10 14601 147526
Montaione FI 11 3700 151226
Castelfranco di Sotto PI 12 13427 164653
Cerreto Guidi FI 12 10870 175523
Capraia e Limite FI 13 7670 183193
Gambassi Terme FI 14 4870 188063
Montelupo Fiorentino FI 15 14098 202161
Santa Maria a Monte PI 16 13253 215414
Vinci FI 16 14604 230018
Montespertoli FI 16 13537 243555
Peccioli PI 17 4807 248362
Capannoli PI 18 6381 254743
Certaldo FI 18 16121 270864
Lamporecchio PT 19 7508 278372
Larciano PT 19 6394 284766
Pontedera PI 19 29223 313989
Ponsacco PI 20 15611 329600

Municipalities with at least 50000 inhabitants

An earthquake occurred to
27 Km W of Scandicci (50609 inhabitants)
31 Km SW of Prato (191150 inhabitants)
32 Km S of Pistoia (90315 inhabitants)
33 Km W of Firenze (382808 inhabitants)
37 Km SE of Lucca (89046 inhabitants)
39 Km E of Pisa (89158 inhabitants)
47 Km E of Livorno (159219 inhabitants)
52 Km NW of Siena (53903 inhabitants)
56 Km E of Viareggio (62467 inhabitants)
73 Km SE of Massa (69479 inhabitants)
78 Km SE of Carrara (63133 inhabitants)
84 Km W of Arezzo (99543 inhabitants)
98 Km SE of La Spezia (93959 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 2.5
ML-VAX 2.4 		1991-07-19
23:42:44		 43.652 10.876 10 2013-07-15
08:41:04		 Bollettino Sismico Italiano INGV 145869
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 1991-07-19 23:42:44 ± 0.231
Latitude 43.6520 ± 0.0183
Longitude 10.8760 ± 0.0115
Depth (km) 10 (operator assigned)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-VAX
Event type earthquake
Origin ID 145869

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) 2236.2
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 193
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) 0.2
Epicentral distance of station closest to the epicenter (degree) 0.00235
Epicentral distance of station farthest from the epicenter (degree) 0.00696
Number of stations at which the event was observed 8
Number of stations from which data was used for origin computation 8
Magnitudes information

Md:2.5

Field Value
Value 2.5
Uncertainty
Num. used stations 4
Type of magnitude Md
Reference to an origin 145869
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2013-01-04 19:16:10

ML:2.4

Field Value
Value 2.4
Uncertainty
Num. used stations 2
Type of magnitude ML
Reference to an origin 145869
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(km) Takeoff_angle Residual Weight
--.CRE.Z. 1991-07-19T23:43:10.50 10.0 undecidable manual SG 91 0.777 -0.84 0
--.SFI.Z. 1991-07-19T23:43:09.43 10.0 undecidable manual SG 69 0.7326 -0.84 0
--.MME.Z. 1991-07-19T23:43:03.50 10.0 undecidable manual SG 346 0.5439 -0.69 0.1
--.BDI.Z. 1991-07-19T23:43:00.47 10.0 undecidable manual SG 333 0.444 -0.54 0.2
--.SFI.Z. 1991-07-19T23:42:59.28 10.0 undecidable manual PG 69 0.7326 -0.08 1.4
--.CRE.Z. 1991-07-19T23:42:59.87 10.0 undecidable manual PG 91 0.777 -0.1 1.4
--.MME.Z. 1991-07-19T23:42:56.00 10.0 undecidable manual PG 346 0.5439 0.16 1.6
--.VMG.Z. 1991-07-19T23:42:56.70 10.0 undecidable manual PG 56 0.5661 0.55 0.6
--.SEI.Z. 1991-07-19T23:42:55.80 10.0 undecidable manual PG 40 0.5328 0.4 1
--.PII.Z. 1991-07-19T23:42:54.70 10.0 undecidable manual SG 285 0.2553 -0.11 0.7
--.BDI.Z. 1991-07-19T23:42:54.22 10.0 undecidable manual PG 333 0.444 0.21 1.5
--.PTF.Z. 1991-07-19T23:42:52.00 10.0 undecidable manual PG 24 0.333 0.2 1.5
--.PII.Z. 1991-07-19T23:42:50.24 10.0 negative manual PG 285 0.2553 -0.18 3.1
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