Quake activity along the San Andreas fault is picking up

San Andreas is on the move...

New seismic hazard assessment for Central America

A new study evaluates the seismic hazards for the entire Central America, including specific assessments for six capital cities, with the greatest hazard expected for Guatemala City and San Salvador, followed by Managua and San José, and notably lower in Tegucigalpa and Panamá City.

The study, published in the April issue of the Bulletin of the Seismological Society of America (BSSA), included input from seismic hazard experts from Costa Rica, Guatemala, Honduras, Nicaragua, El Salvador, Panama, Norway and Spain. All seismic experts from Central American countries, except Belize, agree with the study’s assessments.

This is the first study developed in Central America at a regional scale this century and the first done in terms of peak ground acceleration (PGA) and different spectral acceleration values for the entire region. The study provides new information that is being considered in the revision of national seismic codes and it is also supported by the Coordination Centre for Natural Disasters Prevention in Central America (CEPREDENAC).

Pattern of large earthquakes on San Jacinto fault identified with help of LiDAR

The San Jacinto Fault (SJF) Zone is a seismically active, major component of the overall southern San Andreas Fault system. Researchers from San Diego State University (SDSU) and U.S. Geological Survey have mapped evidence of past ruptures consistent with very large earthquakes along the Clark Fault, an individual strand associated with the SJF.

James Barrett Salisbury, now at Arizona State University and formerly a graduate student at SDSU, and his colleagues mapped the terrain by using both LiDAR and traditional field methods in order to determine the usefulness of LiDAR, which is an aerial mapping technology that emits laser pulses from an instrument mounted in an airplane. The laser pulses penetrate dense vegetation, allowing for the vegetation to be removed in data processing to yield high-resolution images of the Earth's surface. LiDAR is especially useful for analyzing rugged, poorly accessible terrain.

Salisbury and his colleagues identified geomorphic evidence that suggests three large seismic events at evenly spaced intervals along the Clark Fault. This evidence correlates with previous research by co-author Tom Rockwell who dated events at the Hog Lake paleoseismic site near Anza, Calif.

Earthquake activity has really been picking up since the big earthquake off the coast of Russia about 10 days ago. I've got a feeling that the San Andreas is going to have a major slip very soon. Might also be some major activity in Alaska too.



Watch the USGS animation from the last 10 days to see what's going on.

http://earthquake.usgs.gov/eqcenter/recenteqsanim/us.php

http://www.bloomberg.com/apps/news?pid=20601103&sid=a10l5R33hwvs&refer=us

Quote:

Earthquake of Magnitude 6.2 Strikes Off Northern California

By Heather Langan

Nov. 28 (Bloomberg) -- An earthquake of magnitude 6.2 struck off California’s northern coast, the U.S. Geological Survey said in an e-mailed alert.

The temblor struck at 5:43 a.m. local time today, at a depth of 62 miles (100 kilometers), the USGS said. The quake took place 133 miles west of Eureka, California, the monitoring agency said.

http://www.news10.net/news/story.aspx?storyid=51244&catid=2

Quote:

Earthquake Series Continue Across California
Written for the web byPosted By: Jason Kobely, Internet News Producer

Created: 11/29/2008 2:49:41 PM Updated: 11/29/2008 2:53:15 PM

AROMAS, Calif. (AP) -- Four small earthquakes struck Central and Southern California early Saturday, but there are no reports of damage or injuries.

The U.S. Geological Survey said a magnitude-4.1 quake hit the Ridgecrest area of Kern County shortly before 1:15 p.m. The same area had a 3.2-magnitude quake at 3 this morning.

Two earthquakes also struck the Salinas Valley along the Central Coast.

A magnitude-3.2 quake hit just before 5 Saturday morning and a second quake of the same magnitude followed two minutes later.

The quakes were centered near the town of Aromas and about 35 miles from San Jose.

A 3.0-magnitude quake struck the same area at about 10:30 Friday night.

The latest tumblor came after an earthquake of magnitude 6.2 struck off California's northern coast about 133 miles west of Eureka Thursday.