Earthquake with magnitude of Md 2.3 on date 22-10-1987 and time 21:56:44 (Italy) in region 8 km SE Casola Valsenio (RA)

A magnitude Md 2.3 earthquake occured in region: 8 km SE Casola Valsenio (RA), on

  • 22-10-1987 20:56:44 (UTC)
  • 22-10-1987 21:56:44 (UTC +01:00) Italian time

and geographic coordinates (lat, lon) 44.16, 11.68 at 8 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
Casola Valsenio RA 9 2617 2617
Modigliana FC 9 4560 7177
Brisighella RA 10 7639 14816
Tredozio FC 10 1212 16028
Marradi FI 11 3139 19167
Palazzuolo sul Senio FI 12 1154 20321
Riolo Terme RA 14 5720 26041
Fontanelice BO 15 1943 27984
Borgo Tossignano BO 15 3288 31272
Castel del Rio BO 15 1246 32518
Casalfiumanese BO 16 3438 35956
Portico e San Benedetto FC 17 756 36712
Rocca San Casciano FC 17 1910 38622
Dovadola FC 17 1653 40275

Municipalities with at least 50000 inhabitants

An earthquake occurred to
22 Km SW of Faenza (58541 inhabitants)
22 Km S of Imola (69797 inhabitants)
30 Km W of Forlì (117913 inhabitants)
45 Km W of Cesena (96758 inhabitants)
46 Km SE of Bologna (386663 inhabitants)
51 Km SW of Ravenna (159116 inhabitants)
55 Km NE of Firenze (382808 inhabitants)
56 Km NE of Prato (191150 inhabitants)
60 Km NE of Scandicci (50609 inhabitants)
66 Km E of Pistoia (90315 inhabitants)
72 Km W of Rimini (147750 inhabitants)
76 Km S of Ferrara (133155 inhabitants)
79 Km N of Arezzo (99543 inhabitants)
81 Km SE of Modena (184973 inhabitants)
94 Km SE of Carpi (70699 inhabitants)
97 Km N of Siena (53903 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 2.3
ML-VAX 1.8
1987-10-22
20:56:44
44.16 11.68 8 2013-07-15
08:40:51
Bollettino Sismico Italiano INGV 57469
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 1987-10-22 20:56:44 ± 0.796
Latitude 44.16 ± 0.03
Longitude 11.68 ± 0.08
Depth (km) 8 ± 3 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-VAX
Event type earthquake
Origin ID 57469

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) 7221.1
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 311
Number of associated phases, regardless of their use for origin computation 10
Number of defining phases 10
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) 0.00235
Epicentral distance of station farthest from the epicenter (degree) 0.01166
Number of stations at which the event was observed 5
Number of stations from which data was used for origin computation 5
Magnitudes information

Md:2.3

Field Value
Value 2.3
Uncertainty
Num. used stations 3
Type of magnitude Md
Reference to an origin 57469
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2013-01-04 17:55:06

ML:1.8

Field Value
Value 1.8
Uncertainty
Num. used stations 2
Type of magnitude ML
Reference to an origin 57469
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
--.ASS.Z. 1987-10-22T20:57:26.50 10.0 undecidable manual SN 147 0.0117 -0.07 0.7
--.ARV.Z. 1987-10-22T20:57:23.00 10.0 undecidable manual SN 125 0.0101 0.64 0.5
--.ASS.Z. 1987-10-22T20:57:08.80 10.0 undecidable manual PN 147 0.0117 -0.06 1.7
--.ARV.Z. 1987-10-22T20:57:07.00 10.0 undecidable manual PN 125 0.0101 0.57 1.3
--.CRE.Z. 1987-10-22T20:57:04.52 10.0 undecidable manual SG 160 0.0051 -0.78 0.5
--.CRE.Z. 1987-10-22T20:56:56.15 10.0 undecidable manual PG 160 0.0051 -0.44 2
--.PGD.Z. 1987-10-22T20:56:56.43 10.0 undecidable manual SG 173 0.0025 0.38 0.7
--.SS9.Z. 1987-10-22T20:56:55.74 10.0 undecidable manual SG 152 0.0023 0.32 0.5
--.PGD.Z. 1987-10-22T20:56:51.67 10.0 undecidable manual PG 173 0.0025 0.43 1.7
--.SS9.Z. 1987-10-22T20:56:49.29 10.0 undecidable manual PG 152 0.0023 -1.59 0.5
TDMT - Time Domain Moment Tensor
Focal Mechanism in the area
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