Earthquake with magnitude of Md 3.1 on date 31-07-1985 and time 13:56:32 (UTC) in region 4 km E Nemi (RM)

A magnitude Md 3.1 earthquake occured in region: 4 km E Nemi (RM), on

  • 31-07-1985 13:56:32 (UTC)
  • 31-07-1985 15:56:32 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 41.7230, 12.7600 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
Nemi RM 4 1943 1943
Velletri RM 4 53303 55246
Genzano di Roma RM 6 23970 79216
Rocca di Papa RM 6 17034 96250
Lariano RM 6 13432 109682
Lanuvio RM 7 13632 123314
Ariccia RM 7 19407 142721
Rocca Priora RM 8 11962 154683
Albano Laziale RM 8 41715 196398
Castel Gandolfo RM 9 8997 205395
Monte Compatri RM 10 11978 217373
Marino RM 10 43026 260399
Grottaferrata RM 11 20327 280726
Monte Porzio Catone RM 11 8693 289419
Frascati RM 11 22087 311506
San Cesareo RM 12 15153 326659
Colonna RM 13 4287 330946
Labico RM 13 6379 337325
Artena RM 13 14276 351601
Rocca Massima LT 14 1136 352737
Zagarolo RM 14 17843 370580
Valmontone RM 15 15959 386539
Cisterna di Latina LT 16 36868 423407
Cori LT 16 11065 434472
Ciampino RM 16 38412 472884
Palestrina RM 17 21672 494556
Aprilia LT 17 73446 568002
Gallicano nel Lazio RM 17 6334 574336
Castel San Pietro Romano RM 18 902 575238
Cave RM 18 11287 586525

Municipalities with at least 50000 inhabitants

An earthquake occurred to
4 Km NW of Velletri (53303 inhabitants)
17 Km NE of Aprilia (73446 inhabitants)
22 Km E of Pomezia (62966 inhabitants)
27 Km S of Tivoli (56533 inhabitants)
30 Km SE of Roma (2864731 inhabitants)
31 Km NW of Latina (125985 inhabitants)
31 Km S of Guidonia Montecelio (88673 inhabitants)
32 Km NE of Anzio (54211 inhabitants)
44 Km E of Fiumicino (78395 inhabitants)
88 Km SW of L'Aquila (69753 inhabitants)
90 Km E of Civitavecchia (52991 inhabitants)
94 Km S of Terni (111501 inhabitants)
94 Km SE of Viterbo (67173 inhabitants)
Recent and historical seismicity

These maps show the seismic activity in different time intervals, before the seismic event to which they refer. Data reported in the first two maps come from the analysis carried out in real time by the personnel of the INGV Operating Rooms, immediately after each earthquake. The third map shows data from 1985 to the date of the earthquake: the locations are reviewed by the seismological analysts of the INGV Italian Seismic Bulletin (Bollettino Sismico Italiano dell’INGV). The localization parameters (hypocentral coordinates and magnitude) are the best possible estimate with the data available to the INGV, but are constantly updated according to further data that become available. The location and magnitude parameters, subsequently reviewed by seismological analysts, may vary.

Earthquakes of the 3 days preceding this event

Earthquakes of the 3 days preceding this event

This map shows the earthquake epicenters with magnitude ≥ 0.0, localized with data recorded by the National Seismic Network and other collaborative networks both in Italy and in neighboring countries, in the 72 hours preceding this event. The size of the circle indicates the different classes of magnitude. The colors indicate the different time intervals preceding the seismic event. The black and white star is the epicenter of the current earthquake.
Earthquakes of the 90 days preceding this event

Earthquakes of the 90 days preceding this event

This map shows the earthquake epicenters with magnitude ≥ 2.0, localized with data recorded by the National Seismic Network and other collaborative networks both in Italy and in neighboring countries, in the 90 days preceding this event. The size of the circle indicates the different classes of magnitude. The colors indicate the different time intervals preceding the seismic event. The black and white star is the epicenter of the current earthquake.
Earthquakes from 1985 to the date of the event

Earthquakes from 1985 to the date of the event

This map shows the earthquake epicenters with magnitude ≥ 3.0, localized with data recorded by the National Seismic Network and other collaborative networks both in Italy and in neighboring countries, from 1985 to the date of this event. The size of the circle indicates the different classes of magnitude. The colors indicate the different time intervals preceding the seismic event. The black and white star is the epicenter of the current earthquake.
Earthquakes since 1000 AD until 2019

Earthquakes since 1000 AD until 2019

This map shows the epicenters of the historical earthquakes catalogue CPT15 (Catalogo Parametrico dei Terremoti Italiani, 2015 version 3.0, https://doi.org/10.13127/cpti/cpti15.3) since 1000 AD until 2019. The size of the square indicates the different classes of magnitude. For earthquakes with magnitude ≥ 6.0, it is also shown the year of occurrence and the magnitude value. The black and white star is the epicenter of the current earthquake.
Seismic hazard

Seismic hazard maps provide probabilistic estimates of the earthquake ground shaking exceeding a given threshold in a given geographic region within a given time window. Thus, it is not a deterministic prediction - a target that may be never reached given the complexity of the earthquake physical phenomenon - nor of the maximum expected earthquake since this has extremely low probabilities to occur.

In 2004, it was published the seismic hazard map of Italy (http://zonesismiche.mi.ingv.it) that provides a picture of the most hazardous geographic regions. The seismic hazard map of Italy (GdL MPS, 2004; rif. Ordinanza PCM del 28 aprile 2006, n. 3519, All. 1b) provides the 10% probability of exceedance in 50 years of the horizontal acceleration at rock sites (i.e., Vs30>800 m/s; cat. A, 3.2.1 of the D.M. 14.09.2005).

The colours indicate the various values of the ground acceleration that have 10% to be exceeded within 50 years. In general, the colours associated to low values of acceleration refer to areas that are less hazardous and stronger earthquakes repeat less frequently although they may still occur.

Seismic hazard map

Seismic hazard map

This map shows the seismic hazard map of Italy for the region where the earthquake occurred.
Shakemap
Felt maps
Locations history
Type Magnitude Date and Time (UTC) Latitude Longitude Depth (km) Published time (UTC) Author Location ID
Bulletin
Rev1000
Md 3.1 1985-07-31
13:56:32
41.723 12.76 10 2013-07-15
08:41:04
Bollettino Sismico Italiano INGV 11119
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 1985-07-31 13:56:32 ± 0.523
Latitude 41.7230 ± 0.0287
Longitude 12.7600 ± 0.0342
Depth (km) 10 (operator assigned)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-VAX
Event type earthquake
Origin ID 11119

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) 4270.9
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 227
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) 0.7
Epicentral distance of station closest to the epicenter (degree) 0.00040
Epicentral distance of station farthest from the epicenter (degree) 0.01595
Number of stations at which the event was observed 9
Number of stations from which data was used for origin computation 9
Magnitude information

Md:3.1

Field Value
Value 3.1
Uncertainty
Num. used stations 4
Type of magnitude Md
Reference to an origin 11119
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2013-01-04 17:14:36
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
--.AR1.Z. 1985-07-31T13:57:05.00 10.0 undecidable manual PN 4 1.7649 1.81 0.2
--.PO9.Z. 1985-07-31T13:57:02.00 10.0 undecidable manual SG 8 0.8547 -0.29 0.7
--.CM2.Z. 1985-07-31T13:57:00.00 10.0 undecidable manual PN 10 1.4874 0.71 1
--.SD1.Z. 1985-07-31T13:57:00.00 10.0 undecidable manual SG 90 0.777 0.23 0.7
--.AQU.Z. 1985-07-31T13:56:59.00 10.0 undecidable manual SG 36 0.777 -1 0.4
--.AS1.Z. 1985-07-31T13:56:58.50 10.0 undecidable manual PN 356 1.3431 1.33 0.5
--.MNS.Z. 1985-07-31T13:56:56.00 10.0 undecidable manual SG 354 0.6549 0.05 0.7
--.ALP.Z. 1985-07-31T13:56:56.00 10.0 undecidable manual PN 29 1.1988 0.58 1.2
--.SD1.Z. 1985-07-31T13:56:48.00 10.0 undecidable manual PG 90 0.777 -0.33 1.6
--.AQU.Z. 1985-07-31T13:56:48.00 10.0 undecidable manual PG 36 0.777 -0.46 1.5
--.PO9.Z. 1985-07-31T13:56:48.70 10.0 undecidable manual PG 8 0.8547 -1.08 0.9
--.MNS.Z. 1985-07-31T13:56:45.90 10.0 undecidable manual PG 354 0.6549 -0.22 1.7
--.RDP.Z. 1985-07-31T13:56:34.00 10.0 positive manual PG 317 0.0444 -0.97 2
TDMT - Time Domain Moment Tensor
Fault Plane solutions in the area
Fault Plane solutions

Fault Plane solutions

The map reports the fault plane solutions for earthquakes in the region from 1977 to the date of this event. Red moment tensors are determined using the Regional Centroid Moment Tensor technique (RCMT, http://www.bo.ingv.it/RCMT) applied for earthquakes with magnitude larger than 4.5 in the Euro-Mediterranenan area. Occasionally, when a station azimuthal coverage exists RCMTs can be obtained also for earthquakes with magnitude down to 4.0. The gray moment tensors are obtained with the Time Domain Moment Tensor method (TDMT, /tdmt). This technique is applied to earthquakes with magnitude ML greater than 3.2, when it is possible. The size of symbols scales with the calculated moment magnitude Mw.
Download
Type Description Link
QuakeML - small Event, Origin, FocalMechanism Download
QuakeML - full Event, Origin, FocalMechanism, Amplitude, Arrival, Pick, Station Magnitude Download