Global & Disaster Medicine

Archive for January, 2018

Peru: Adobe structures destroyed in quake and at least one person dead

https://www.youtube.com/watch?v=rL6EZ6wqJMg


Talk about “lucky!”


M 7.1 – 40km SSW of Acari, Peru

ShakeMap Intensity image

 

09:18:45 UTC

15.776°S   74.744°W

36.3 km depth

Seismotectonics of South America (Nazca Plate Region)

The South American arc extends over 7,000 km, from the Chilean margin triple junction offshore of southern Chile to its intersection with the Panama fracture zone, offshore of the southern coast of Panama in Central America. It marks the plate boundary between the subducting Nazca plate and the South America plate, where the oceanic crust and lithosphere of the Nazca plate begin their descent into the mantle beneath South America. The convergence associated with this subduction process is responsible for the uplift of the Andes Mountains, and for the active volcanic chain present along much of this deformation front. Relative to a fixed South America plate, the Nazca plate moves slightly north of eastwards at a rate varying from approximately 80 mm/yr in the south to approximately 65 mm/yr in the north. Although the rate of subduction varies little along the entire arc, there are complex changes in the geologic processes along the subduction zone that dramatically influence volcanic activity, crustal deformation, earthquake generation and occurrence all along the western edge of South America.

USGS:  Understanding plate motions

Most of the large earthquakes in South America are constrained to shallow depths of 0 to 70 km resulting from both crustal and interplate deformation. Crustal earthquakes result from deformation and mountain building in the overriding South America plate and generate earthquakes as deep as approximately 50 km. Interplate earthquakes occur due to slip along the dipping interface between the Nazca and the South American plates. Interplate earthquakes in this region are frequent and often large, and occur between the depths of approximately 10 and 60 km. Since 1900, numerous magnitude 8 or larger earthquakes have occurred on this subduction zone interface that were followed by devastating tsunamis, including the 1960 M9.5 earthquake in southern Chile, the largest instrumentally recorded earthquake in the world. Other notable shallow tsunami-generating earthquakes include the 1906 M8.5 earthquake near Esmeraldas, Ecuador, the 1922 M8.5 earthquake near Coquimbo, Chile, the 2001 M8.4 Arequipa, Peru earthquake, the 2007 M8.0 earthquake near Pisco, Peru, and the 2010 M8.8 Maule, Chile earthquake located just north of the 1960 event.

Large intermediate-depth earthquakes (those occurring between depths of approximately 70 and 300 km) are relatively limited in size and spatial extent in South America, and occur within the Nazca plate as a result of internal deformation within the subducting plate. These earthquakes generally cluster beneath northern Chile and southwestern Bolivia, and to a lesser extent beneath northern Peru and southern Ecuador, with depths between 110 and 130 km. Most of these earthquakes occur adjacent to the bend in the coastline between Peru and Chile. The most recent large intermediate-depth earthquake in this region was the 2005 M7.8 Tarapaca, Chile earthquake.

Earthquakes can also be generated to depths greater than 600 km as a result of continued internal deformation of the subducting Nazca plate. Deep-focus earthquakes in South America are not observed from a depth range of approximately 300 to 500 km. Instead, deep earthquakes in this region occur at depths of 500 to 650 km and are concentrated into two zones: one that runs beneath the Peru-Brazil border and another that extends from central Bolivia to central Argentina. These earthquakes generally do not exhibit large magnitudes. An exception to this was the 1994 Bolivian earthquake in northwestern Bolivia. This M8.2 earthquake occurred at a depth of 631 km, which was until recently the largest deep-focus earthquake instrumentally recorded (superseded in May 2013 by a M8.3 earthquake 610 km beneath the Sea of Okhotsk, Russia), and was felt widely throughout South and North America.

Subduction of the Nazca plate is geometrically complex and impacts the geology and seismicity of the western edge of South America. The intermediate-depth regions of the subducting Nazca plate can be segmented into five sections based on their angle of subduction beneath the South America plate. Three segments are characterized by steeply dipping subduction; the other two by near-horizontal subduction. The Nazca plate beneath northern Ecuador, southern Peru to northern Chile, and southern Chile descend into the mantle at angles of 25° to 30°. In contrast, the slab beneath southern Ecuador to central Peru, and under central Chile, is subducting at a shallow angle of approximately 10° or less. In these regions of “flat-slab” subduction, the Nazca plate moves horizontally for several hundred kilometers before continuing its descent into the mantle, and is shadowed by an extended zone of crustal seismicity in the overlying South America plate. Although the South America plate exhibits a chain of active volcanism resulting from the subduction and partial melting of the Nazca oceanic lithosphere along most of the arc, these regions of inferred shallow subduction correlate with an absence of volcanic activity.

More information on regional seismicity and tectonics


Hawaii: Rat lungworm disease has increased in severity.

Hawaii Tribune-Herald

“…..[the worries of]  global warming and the possibility East
Hawaii’s rat lungworm problem will spread as the range of infested
snails grows on the mainland in the years ahead.

Angiostrongylus cantonensis Lifecycle

 


2017-2018 Influenza Season Week 1 ending January 6, 2018

CDC

During week 1 (December 31, 2017-January 6, 2018), influenza activity increased in the United States.

  • Viral Surveillance: The most frequently identified influenza virus subtype reported by public health laboratories during week 1 was influenza A(H3). The percentage of respiratory specimens testing positive for influenza in clinical laboratories remained elevated.
  • Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was at the system-specific epidemic threshold in the National Center for Health Statistics (NCHS) Mortality Surveillance System.
  • Influenza-associated Pediatric Deaths: Seven influenza-associated pediatric deaths were reported.
  • Influenza-associated Hospitalizations: A cumulative rate of 22.7 laboratory-confirmed influenza-associated hospitalizations per 100,000 population was reported.
  • Outpatient Illness Surveillance:The proportion of outpatient visits for influenza-like illness (ILI) was 5.8%, which is above the national baseline of 2.2%. All 10 regions reported ILI at or above region-specific baseline levels. New York City and 26 states experienced high ILI activity; Puerto Rico and 10 states experienced moderate ILI activity; the District of Columbia and six states experienced low ILI activity; and eight states experienced minimal ILI activity.
  • Geographic Spread of Influenza:The geographic spread of influenza in 49 states was reported as widespread; Guam and one state reported regional activity; the District of Columbia reported local activity; the U.S. Virgin Islands reported sporadic activity; and Puerto Rico did not report.

INFLUENZA Virus Isolated

Click on image to launch interactive tool

Click on graph to launch interactive tool

national levels of ILI and ARI

 


A false alarm in Hawaii: 38 minutes elapsed before emergency systems sent a second message announcing the mistake. Many more mistakes could “domino” in a 1/2 minute — like nuclear war!

NY Times

 


1/13/1982: An Air Florida Boeing 727 plunges into the Potomac River in Washington, D.C., killing 78 people.

History Channel

 


An arctic front will bring a wintry mix of heavy snow, ice, dramatically colder temperatures, and gusty winds from the Middle Atlantic to the Northeast Saturday. Ice accumulations up to a quarter of an inch could cause power outages and create hazardous travel conditions. Later this weekend and early next week, a new arctic front will bring widespread snow from the Plains to the Great Lakes.

TWC

National Weather Outlook

SPC Products Overview

 


Just before 5 p.m. on Jan. 12, 2010, a 7.0M earthquake upended Haiti, killing more than 300,000 people by some estimates and destroying hundreds of thousands of homes.

Washington Post

 


The Las Vegas Massacre

https://nyti.ms/2zrS80q

https://nyti.ms/2gX5Nps

Las Vegas Gunman Took Elaborate Steps to Hide His Tracks

 


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