Earthquake with magnitude of Md 2.5 on date 25-04-1987 and time 23:30:22 (Italy) in region 5 km NW Narni (TR)

A magnitude Md 2.5 earthquake occured in region: 5 km NW Narni (TR), on

  • 25-04-1987 21:30:22 (UTC)
  • 25-04-1987 23:30:22 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 42.56, 12.49 at 32 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
Narni TR 5 19785 19785
Amelia TR 7 11897 31682
San Gemini TR 7 5018 36700
Montecastrilli TR 10 5022 41722
Avigliano Umbro TR 11 2558 44280
Terni TR 13 111501 155781
Lugnano in Teverina TR 13 1494 157275
Penna in Teverina TR 14 1099 158374
Orte VT 14 8923 167297
Acquasparta TR 15 4778 172075
Giove TR 15 1928 174003
Otricoli TR 16 1869 175872
Stroncone TR 16 4917 180789
Alviano TR 16 1463 182252
Guardea TR 17 1836 184088
Attigliano TR 17 2028 186116
Bassano in Teverina VT 19 1313 187429
Calvi dell'Umbria TR 19 1856 189285
Configni RI 20 633 189918
Montecchio TR 20 1676 191594

Municipalities with at least 50000 inhabitants

An earthquake occurred to
13 Km W of Terni (111501 inhabitants)
36 Km E of Viterbo (67173 inhabitants)
47 Km SW of Foligno (57155 inhabitants)
61 Km S of Perugia (166134 inhabitants)
66 Km NW of Guidonia Montecelio (88673 inhabitants)
71 Km NW of Tivoli (56533 inhabitants)
75 Km N of Roma (2864731 inhabitants)
78 Km NE of Civitavecchia (52991 inhabitants)
78 Km W of L'Aquila (69753 inhabitants)
91 Km N of Fiumicino (78395 inhabitants)
99 Km N of Pomezia (62966 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 2.5 1987-04-25
21:30:22
42.57 12.49 32 2013-07-15
08:40:51
Bollettino Sismico Italiano INGV 45689
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 1987-04-25 21:30:22 ± 0.214
Latitude 42.57 ± 0.01
Longitude 12.49 ± 0.04
Depth (km) 32 ± 2 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-VAX
Event type earthquake
Origin ID 45689

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) 3359
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 219
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) 0.1
Epicentral distance of station closest to the epicenter (degree) 0.00202
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
Magnitude information

Md:2.5

Field Value
Value 2.5
Uncertainty
Num. used stations 2
Type of magnitude Md
Reference to an origin 45689
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2013-01-04 17:44:58
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
--.SDI.Z. 1987-04-25T21:30:59.50 10.0 undecidable manual S 130 0.0117 -0.27 0.2
--.ARV.Z. 1987-04-25T21:30:53.00 10.0 undecidable manual S 19 0.0089 0.52 0
--.CP9.Z. 1987-04-25T21:30:47.50 10.0 undecidable manual S 154 0.007 -0.02 0.8
--.SDI.Z. 1987-04-25T21:30:44.00 10.0 undecidable manual P 130 0.0117 0.05 1.4
--.ASS.Z. 1987-04-25T21:30:41.00 10.0 undecidable manual S 13 0.0045 -0.09 1.1
--.ARV.Z. 1987-04-25T21:30:39.50 10.0 undecidable manual P 19 0.0089 -0.23 0.9
--.CP9.Z. 1987-04-25T21:30:37.00 10.0 undecidable manual P 154 0.007 0.13 1.5
--.MNS.Z. 1987-04-25T21:30:34.50 10.0 undecidable manual S 142 0.002 -0.09 1.1
--.ASS.Z. 1987-04-25T21:30:33.00 10.0 undecidable manual P 13 0.0045 -0.16 1.4
--.MNS.Z. 1987-04-25T21:30:29.50 10.0 undecidable manual P 142 0.002 0.1 1.7
TDMT - Time Domain Moment Tensor
Focal Mechanism in the area
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