Earthquake with magnitude of Md 2.5 on date 27-08-1991 and time 03:20:00 (UTC) in region 4 km NW Montieri (GR)

A magnitude Md 2.5 earthquake occured in region: 4 km NW Montieri (GR), on

  • 27-08-1991 03:20:00 (UTC)
  • 27-08-1991 05:20:00 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 43.1560, 10.9770 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
Montieri GR 4 1204 1204
Castelnuovo di Val di Cecina PI 8 2231 3435
Chiusdino SI 9 1903 5338
Monterotondo Marittimo GR 10 1371 6709
Radicondoli SI 13 914 7623
Massa Marittima GR 14 8375 15998
Monticiano SI 17 1571 17569
Pomarance PI 18 5897 23466

Municipalities with at least 50000 inhabitants

An earthquake occurred to
34 Km SW of Siena (53903 inhabitants)
45 Km N of Grosseto (82087 inhabitants)
69 Km S of Scandicci (50609 inhabitants)
70 Km SE of Livorno (159219 inhabitants)
72 Km SW of Firenze (382808 inhabitants)
78 Km SE of Pisa (89158 inhabitants)
81 Km W of Arezzo (99543 inhabitants)
81 Km S of Prato (191150 inhabitants)
86 Km SE of Lucca (89046 inhabitants)
87 Km S of Pistoia (90315 inhabitants)
99 Km SE of Viareggio (62467 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 2.1
1991-08-27
03:20:00
43.156 10.977 10 2013-07-15
08:40:51
Bollettino Sismico Italiano INGV 148189
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 1991-08-27 03:20:00 ± 0.71
Latitude 43.1560 ± 0.0105
Longitude 10.9770 ± 0.0245
Depth (km) 10 ± 6 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-VAX
Event type earthquake
Origin ID 148189

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) 2305.3
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 159
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) 0.2
Epicentral distance of station closest to the epicenter (degree) 0.00583
Epicentral distance of station farthest from the epicenter (degree) 0.00947
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:2.5

Field Value
Value 2.5
Uncertainty
Num. used stations 5
Type of magnitude Md
Reference to an origin 148189
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2013-01-04 19:18:18

ML:2.1

Field Value
Value 2.1
Uncertainty
Num. used stations 4
Type of magnitude ML
Reference to an origin 148189
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
--.MME.Z. 1991-08-27T03:20:36.71 10.0 undecidable manual SN 348 1.0545 0.93 0.1
--.SFI.Z. 1991-08-27T03:20:32.68 10.0 undecidable manual SG 39 0.9657 -0.82 0.1
--.PGD.Z. 1991-08-27T03:20:31.28 10.0 undecidable manual SG 36 0.888 0.34 0.5
--.BDI.Z. 1991-08-27T03:20:31.16 10.0 undecidable manual SG 342 0.9435 -1.31 0
--.CRE.Z. 1991-08-27T03:20:28.93 10.0 undecidable manual SG 56 0.8436 -0.31 0.5
--.MAO.Z. 1991-08-27T03:20:25.84 10.0 undecidable manual SG 169 0.7437 -0.32 0.5
--.PII.Z. 1991-08-27T03:20:22.10 10.0 undecidable manual SG 329 0.6438 -1.05 0
--.MME.Z. 1991-08-27T03:20:21.21 10.0 undecidable manual PN 348 1.0545 0.49 0.8
--.SFI.Z. 1991-08-27T03:20:19.34 10.0 undecidable manual PG 39 0.9657 -0.07 1.5
--.PGD.Z. 1991-08-27T03:20:18.30 10.0 undecidable manual PG 36 0.888 0.1 1.5
--.BDI.Z. 1991-08-27T03:20:18.95 10.0 undecidable manual PG 342 0.9435 0.13 1.4
--.CRE.Z. 1991-08-27T03:20:17.90 10.0 positive manual PG 56 0.8436 0.14 3
--.MAO.Z. 1991-08-27T03:20:15.50 10.0 positive manual PG 169 0.7437 -0.12 3
--.PII.Z. 1991-08-27T03:20:13.75 10.0 undecidable manual PG 329 0.6438 0.37 1.1
TDMT - Time Domain Moment Tensor
Fault Plane solutions in the area
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Type Description Link
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