Earthquake near Puerto Rico in 1918
| Earthquake near Puerto Rico in 1918 | |||
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| date | October 11, 1918 | ||
| Time | 14:14:42 UTC | ||
| intensity | X on the MM scale | ||
| Magnitude | 7.1 M W | ||
| depth | 15 km | ||
| epicenter | 18 ° 48 '7 " N , 67 ° 13' 8" W | ||
| country | Puerto Rico | ||
| Tsunami | Yes | ||
| dead | 116 | ||
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The Puerto Rico earthquake in 1918 was one of the worst in the island's history. It occurred on October 11, 1918 at 10:14 a.m. local time and had a magnitude of 7.1 M w . It caused a tsunami and was accompanied by numerous aftershocks.
Tectonic background
Puerto Rico and the Virgin Islands lie on a small microplate between the North American and Caribbean plates . The western edge of this microplate is formed by the North-South oriented Mona Canyon , an undersea canyon in the Mona Passage , which is criss-crossed by several faults . The earthquake had its epicenter there , around 42 kilometers north-northwest of Aguadilla . His source of the quake was at a depth of 15 kilometers.
By March 1919, 112 aftershocks had been registered, the strongest on October 24 and November 12, 1918.
Tsunami
Minutes after the quake, a tsunami hit the west coast of Puerto Rico. The largest wave height of over 6 meters he reached in the northwest of the island. The sea had previously been observed to retreat below the level of the deepest ebb tide .
2004 and 2006 with the research vessels NOAA's Ronald H. Brown and RV Pelican derived bathymetric and seismic reflection data suggest that the quake square kilometers in an area of 76 an undersea landslide triggered, are set in motion in which about 10 cubic kilometers of seabed and thus likely the tsunami was triggered. Two telegraph lines that were destroyed in the region at the time support this theory.
Victims and damage
116 people were killed in the earthquake. 40 to 100 deaths can be attributed to the tsunami.
The greatest damage occurred in the west and northwest of Puerto Rico. The city hardest hit was Mayagüez , where 700 (brick) stone houses and over 1000 wooden houses were destroyed. Roads, railroad tracks and sea walls were destroyed or badly damaged. Other cities that suffered severe damage include Isabela , Aguada and Añasco . The earthquake had a strong impact in places that were built on flood plains . In the town of Rincón , the effects were less devastating because of the rocky subsoil. There was damage all over the island and on Vieques .
Numerous bridges and chimneys collapsed. There were landslides and soil liquefaction with up to four meters high mud fountains. During the aftershock on October 24, 1918, other buildings collapsed.
The economic damage was then estimated at four million US dollars , which was twice the annual budget of the island.
photos
Partially collapsed house in Mayagüez
Damage in Mayagüez
The church in Mayagüez, the left tower of which collapsed in an aftershock
Ruins of a lighthouse destroyed by the tsunami in Aguadilla
supporting documents
- ↑ a b M 7.1 - Puerto Rico region. USGS , accessed January 8, 2020.
- ↑ a b c d A. M. López-Venegas, US ten Brink, EL Geist: Submarine landslide as the source for the October 11, 1918 Mona Passage tsunami: Observations and modeling. In: Marine Geology , Volume 254. 2008, pp. 35–46, article online at uprm.edu (English; PDF; 3.71 MB).
- ↑ a b c d e Seismic Information: Earthquake of 1918. Puerto Rico Seismic Network, accessed January 8, 2020 (English).
- ↑ a b Peter Aviles: The Devil's Scream ( Memento from May 15, 2004 in the Internet Archive ) (PDF; 934 kB). In: uprm.edu . 2002 (English).