Earthquake with magnitude of Md 2.1 on date 07-04-1991 and time 20:41:20 (UTC) in region 4 km SE Velletri (RM)
A magnitude Md 2.1 earthquake occured in region: 4 km SE Velletri (RM), on
- 07-04-1991 20:41:20 (UTC)
- 07-04-1991 22:41:20 (UTC +02:00) Italian time
and geographic coordinates (lat, lon) 41.6620, 12.8200 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.
Display location by
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Municipalities within 20 km from the epicenter
Distances are determinated based on the geographic coordintes of the (Istat).
| Municipality | Region | Distance (km) | Inhabitants | Cumulative Inhabitants |
|---|---|---|---|---|
| Velletri | RM | 5 | 53303 | 53303 |
| Lariano | RM | 8 | 13432 | 66735 |
| Cisterna di Latina | LT | 8 | 36868 | 103603 |
| Cori | LT | 8 | 11065 | 114668 |
| Rocca Massima | LT | 9 | 1136 | 115804 |
| Lanuvio | RM | 10 | 13632 | 129436 |
| Nemi | RM | 11 | 1943 | 131379 |
| Artena | RM | 12 | 14276 | 145655 |
| Genzano di Roma | RM | 12 | 23970 | 169625 |
| Ariccia | RM | 14 | 19407 | 189032 |
| Rocca di Papa | RM | 15 | 17034 | 206066 |
| Labico | RM | 15 | 6379 | 212445 |
| Valmontone | RM | 15 | 15959 | 228404 |
| Albano Laziale | RM | 15 | 41715 | 270119 |
| Norma | LT | 15 | 3946 | 274065 |
| Rocca Priora | RM | 16 | 11962 | 286027 |
| Aprilia | LT | 16 | 73446 | 359473 |
| Castel Gandolfo | RM | 17 | 8997 | 368470 |
| Colleferro | RM | 17 | 21595 | 390065 |
| Segni | RM | 17 | 9159 | 399224 |
| Monte Compatri | RM | 18 | 11978 | 411202 |
| San Cesareo | RM | 18 | 15153 | 426355 |
| Marino | RM | 18 | 43026 | 469381 |
| Montelanico | RM | 18 | 2131 | 471512 |
| Sermoneta | LT | 19 | 9842 | 481354 |
| Grottaferrata | RM | 19 | 20327 | 501681 |
| Monte Porzio Catone | RM | 19 | 8693 | 510374 |
| Cave | RM | 20 | 11287 | 521661 |
| Gavignano | RM | 20 | 1916 | 523577 |
| Frascati | RM | 20 | 22087 | 545664 |
| Zagarolo | RM | 20 | 17843 | 563507 |
Municipalities with at least 50000 inhabitants
An earthquake occurred to
5 Km SE of Velletri (53303 inhabitants)
16 Km E of Aprilia (73446 inhabitants)
23 Km NW of Latina (125985 inhabitants)
26 Km E of Pomezia (62966 inhabitants)
29 Km NE of Anzio (54211 inhabitants)
34 Km S of Tivoli (56533 inhabitants)
38 Km SE of Roma (2864731 inhabitants)
39 Km S of Guidonia Montecelio (88673 inhabitants)
50 Km E of Fiumicino (78395 inhabitants)
91 Km SW of L'Aquila (69753 inhabitants)
98 Km SE of Civitavecchia (52991 inhabitants)
Recent and historical seismicity
Not available maps for this sismic event.
Seismic hazard
Not available maps for this sismic event.
Shakemap
Not available maps for this sismic event.
Felt maps
Not available maps for this sismic event.
Locations history
| Type | Magnitude | Date and Time (UTC) | Latitude | Longitude | Depth (km) | Published time (UTC) | Author | Location ID |
|---|---|---|---|---|---|---|---|---|
|
Bulletin Rev1000 |
Md 2.1
ML-VAX 1.7 |
1991-04-07 20:41:20 |
41.662 | 12.82 | 10 | 2013-07-15 08:41:04 |
Bollettino Sismico Italiano INGV | 138819 |
Preferred location and magnitude until now.
Origin information
Origin
| Field | Value |
|---|---|
| Time (UTC) | 1991-04-07 20:41:20 ± 0.273 |
| Latitude | 41.6620 ± 0.0141 |
| Longitude | 12.8200 ± 0.0124 |
| Depth (km) | 10 (operator assigned) |
| Evaluation mode of Origin | manual |
| Evaluation status of Origin | reviewed |
| Version | 1000 -> BULLETIN-VAX |
| Event type | earthquake |
| Origin ID | 138819 |
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) | 1874.4 |
| Confidence level of the uncertainty (%) | 68 |
Quality
| Field | Value |
|---|---|
| Largest azimuthal gap in station distribution as seen from epicenter (degree) | 243 |
| 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) | 0.2 |
| Epicentral distance of station closest to the epicenter (degree) | 0.00154 |
| Epicentral distance of station farthest from the epicenter (degree) | 0.00664 |
| 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:2.1
| Field | Value |
|---|---|
| Value | 2.1 |
| Uncertainty | |
| Num. used stations | 3 |
| Type of magnitude | Md |
| Reference to an origin | 138819 |
| Agency | INGV |
| Autore | Bollettino Sismico Italiano INGV |
| Time of creation (UTC) | 2013-01-04 19:09:32 |
ML:1.7
| Field | Value |
|---|---|
| Value | 1.7 |
| Uncertainty | |
| Num. used stations | 3 |
| Type of magnitude | ML |
| Reference to an origin | 138819 |
| 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| --.SDI.Z. | 1991-04-07T20:41:46.71 | 10.0 | undecidable | manual | SG | 85 | 0.7326 | 0.52 | 0.1 | |
| --.MNS.Z. | 1991-04-07T20:41:45.59 | 10.0 | undecidable | manual | SG | 351 | 0.7326 | -0.23 | 0.4 | |
| --.MNS.Z. | 1991-04-07T20:41:35.27 | 10.0 | undecidable | manual | PG | 351 | 0.7326 | 0.15 | 1.4 | |
| --.SDI.Z. | 1991-04-07T20:41:34.94 | 10.0 | undecidable | manual | PG | 85 | 0.7326 | -0.4 | 0.6 | |
| --.CP9.Z. | 1991-04-07T20:41:29.42 | 10.0 | undecidable | manual | SG | 26 | 0.2109 | -0.14 | 0.6 | |
| --.RMP.Z. | 1991-04-07T20:41:27.88 | 10.0 | undecidable | manual | SG | 329 | 0.1665 | -0.08 | 0.9 | |
| --.CP9.Z. | 1991-04-07T20:41:25.91 | 10.0 | undecidable | manual | PG | 26 | 0.2109 | 0.17 | 1.8 | |
| --.RMP.Z. | 1991-04-07T20:41:24.78 | 10.0 | undecidable | manual | PG | 329 | 0.1665 | -0.02 | 2.2 |
TDMT - Time Domain Moment Tensor
Not available TDMT solution for this seismic event.
Fault Plane solutions in the area
Not available maps for this sismic event.