Earthquake with magnitude of Md 2.3 on date 20-09-1987 and time 23:55:17 (Italy) in region 5 km W Montemonaco (AP)

A magnitude Md 2.3 earthquake occured in region: 5 km W Montemonaco (AP), on

  • 20-09-1987 21:55:17 (UTC)
  • 20-09-1987 23:55:17 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 42.9050, 13.2690 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
Montemonaco AP 5 604 604
Montefortino FM 7 1178 1782
Montegallo AP 9 523 2305
Castelsantangelo sul Nera MC 9 281 2586
Bolognola MC 11 142 2728
Amandola FM 11 3629 6357
Ussita MC 12 444 6801
Comunanza AP 13 3166 9967
Arquata del Tronto AP 15 1178 11145
Visso MC 15 1107 12252
Sarnano MC 15 3264 15516
Palmiano AP 16 196 15712
Acquacanina MC 16 121 15833
Fiastra MC 17 559 16392
Roccafluvione AP 18 2010 18402
Montefalcone Appennino FM 18 424 18826
Smerillo FM 18 365 19191
Venarotta AP 19 2066 21257
Norcia PG 19 4957 26214
Preci PG 19 724 26938
Acquasanta Terme AP 19 2916 29854
Gualdo MC 19 815 30669
Force AP 19 1354 32023
Monte San Martino MC 20 765 32788

Municipalities with at least 50000 inhabitants

An earthquake occurred to
45 Km NW of Teramo (54892 inhabitants)
46 Km E of Foligno (57155 inhabitants)
62 Km N of L'Aquila (69753 inhabitants)
64 Km NE of Terni (111501 inhabitants)
75 Km E of Perugia (166134 inhabitants)
82 Km S of Ancona (100861 inhabitants)
84 Km NW of Montesilvano (53738 inhabitants)
91 Km NW of Pescara (121014 inhabitants)
96 Km NW of Chieti (51815 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 2.3
ML-VAX 1.6
1987-09-20
21:55:17
42.905 13.269 10 2013-07-15
08:41:04
Bollettino Sismico Italiano INGV 55769
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 1987-09-20 21:55:17 ± 0.198
Latitude 42.9050 ± 0.0160
Longitude 13.2690 ± 0.0198
Depth (km) 10 (operator assigned)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-VAX
Event type earthquake
Origin ID 55769

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) 2403.5
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 169
Number of associated phases, regardless of their use for origin computation 8
Number of defining phases 8
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) 0.00575
Number of stations at which the event was observed 4
Number of stations from which data was used for origin computation 4
Magnitudes information

Md:2.3

Field Value
Value 2.3
Uncertainty
Num. used stations 1
Type of magnitude Md
Reference to an origin 55769
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2013-01-04 17:53:38

ML:1.6

Field Value
Value 1.6
Uncertainty
Num. used stations 1
Type of magnitude ML
Reference to an origin 55769
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
--.ARV.Z. 1987-09-20T21:55:41.00 10.0 undecidable manual SG 338 0.6327 0.96 0.1
--.ASS.Z. 1987-09-20T21:55:35.20 10.0 undecidable manual SG 289 0.4773 0.35 0.5
--.ARV.Z. 1987-09-20T21:55:31.00 10.0 undecidable manual PG 338 0.6327 0.45 0.9
--.CM8.Z. 1987-09-20T21:55:29.31 10.0 undecidable manual SG 342 0.2997 0.04 1.1
--.ASS.Z. 1987-09-20T21:55:27.47 10.0 undecidable manual PG 289 0.4773 -0.09 1.6
--.ALP.Z. 1987-09-20T21:55:27.95 10.0 undecidable manual SG 119 0.2442 0.38 0.7
--.ALP.Z. 1987-09-20T21:55:23.16 10.0 undecidable manual PG 119 0.2442 -0.2 1.6
--.CM8.Z. 1987-09-20T21:55:23.74 10.0 undecidable manual PG 342 0.2997 -0.59 1.5
TDMT - Time Domain Moment Tensor
Fault Plane solutions in the area
Download
Type Description Link
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QuakeML - full Event, Origin, FocalMechanism, Amplitude, Arrival, Pick, Station Magnitude Download