1997 Umbria and Marche earthquake
Encyclopedia
The 1997 Umbria and Marche earthquake consisted of two earthquake
s that occurred in the regions of Umbria
and Marche
, central
Italy
, in quick succession on the morning of September 26 1997.
The first shock occurred at 2:33 am CEST
(0:33 UTC), rated 5.5 on the Richter scale, and the second – the main shock – occurred at 11:40 am CEST (9:40 UTC), rated 6.1 on the Richter scale. Their epicentre was in Annifo
.
There were several thousands of foreshock
s and aftershock
s from May 1997 to April 1998, more than thirty of which had a Richter magnitude more than 3.5. 11 people are known to have died following the shocks of September 26 1997.
and aftershocks
) with magnitude 5.0 or higher are listed. Shocks with magnitude 5.5 or higher are highlighted in light blue. The main shock with magnitude 6.1 Mw is highlighted in dark blue.
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
s that occurred in the regions of Umbria
Umbria
Umbria is a region of modern central Italy. It is one of the smallest Italian regions and the only peninsular region that is landlocked.Its capital is Perugia.Assisi and Norcia are historical towns associated with St. Francis of Assisi, and St...
and Marche
Marche
The population density in the region is below the national average. In 2008, it was 161.5 inhabitants per km2, compared to the national figure of 198.8. It is highest in the province of Ancona , and lowest in the province of Macerata...
, central
Central Italy
Central Italy is one of the five official statistical regions of Italy used by the National Institute of Statistics , a first level NUTS region and a European Parliament constituency...
Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, in quick succession on the morning of September 26 1997.
The first shock occurred at 2:33 am CEST
Central European Summer Time
Central European Summer Time is one of the names of the Daylight saving time offset using the UTC offset of UTC+02:00, 2 hours ahead of Coordinated Universal Time. It is used as a summer daylight saving time in most European countries. During the winter, Central European Time is used...
(0:33 UTC), rated 5.5 on the Richter scale, and the second – the main shock – occurred at 11:40 am CEST (9:40 UTC), rated 6.1 on the Richter scale. Their epicentre was in Annifo
Annifo
Annifo is a frazione of the comune of Foligno, Umbria, central Italy. It is located at 874 m. According to the Istat census of 2001, it has 244 inhabitants....
.
There were several thousands of foreshock
Foreshock
A foreshock is an earthquake that occurs before a larger seismic event and is related to it in both time and space. The designation of an earthquake as foreshock, mainshock or aftershock is only possible after the event....
s and aftershock
Aftershock
An aftershock is a smaller earthquake that occurs after a previous large earthquake, in the same area of the main shock. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock...
s from May 1997 to April 1998, more than thirty of which had a Richter magnitude more than 3.5. 11 people are known to have died following the shocks of September 26 1997.
List of foreshocks and aftershocks
Only shocks (both foreshocksForeshock
A foreshock is an earthquake that occurs before a larger seismic event and is related to it in both time and space. The designation of an earthquake as foreshock, mainshock or aftershock is only possible after the event....
and aftershocks
Aftershock
An aftershock is a smaller earthquake that occurs after a previous large earthquake, in the same area of the main shock. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock...
) with magnitude 5.0 or higher are listed. Shocks with magnitude 5.5 or higher are highlighted in light blue. The main shock with magnitude 6.1 Mw is highlighted in dark blue.
| Date (YYYY-MM-DD) | Time (UTC) | Latitude Latitude In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a... | Longitude Longitude Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda .... | Depth | Magnitude |
|---|---|---|---|---|---|
| 1997-09-26 | 0:33:12 | 43.048° N | 12.879° E | 10 km (6 mi) | 5.5 (Mw) |
| 1997-09-26 | 11:40:26 | 43.084° N | 12.812° E | 10 km (6 mi) | 6.1 (Mw) |
| 1997-09-26 | 9:47:38 | 43.163° N | 12.752° E | 10 km (6 mi) | 4.7 (ML) |
| 1997-10-03 | 8:55:21 | 43.075° N | 12.794° E | 10 km (6 mi) | 5.3 (Mw) |
| 1997-10-06 | 23:24:52 | 43.045° N | 12.835° E | 10 km (6 mi) | 5.5 (Mw) |
| 1997-10-12 | 11:08:36 | 42.901° N | 12.897° E | 10 km (6 mi) | 5.3 (ML) |
| 1997-10-14 | 15:23:10 | 42.962° N | 12.892° E | 10 km (6 mi) | 5.6 (ML) |
| 1997-11-09 | 19:07:33 | 42.903° N | 12.948° E | 10 km (6 mi) | 5.0 (ML) |
| 1998-03-26 | 16:26:11 | 43.255° N | 12.969° E | 10 km (6 mi) | 5.4 (Mw) |
| 1998-04-03 | 7:26:36 | 43.164° N | 12.701° E | 10 km (6 mi) | 5.2 (Mw) |
| 1998-04-05 | 15:52:20 | 43.185° N | 12.719° E | 10 km (6 mi) | 5.0 (ML) |