Posts tagged Earthquake hazards
IRIS (Incorporated Research Institutions for Seismology) hosts and distributes a new computer display system, Active Earth Monitor. Designed for K-12 schools, museums, visitor centers and libraries, Active Earth Monitor provides an interactive environment for learning earth science topics.
From IRIS’s description, “All Active Earth Monitor content can be interactive using a touch screen, mouse or trackball. The General Seismicity content can also be displayed as rotating non-interactive content using a standard monitor.”
Active Earth Monitor promises to be a powerful tool for visualizing Earth science processes. Anyone with a computer, monitor, good internet connection, and desire to share information can establish their own Active Earth Monitor. Give it a look.
FEMA training in Somerton, AZ, today focused on ATC-20; evaluating building safety/integrity following an earthquake. Chiefly we reviewed the ATC-20 form and engaged in discussion on how to recognize building type – i.e., material (wood, steel, concrete, unreinforced masonry) — and how to recognize potential structural and non-structural hazards. We were then presented with a suite of slides of damaged buildings and using the ATC-20 posting system — green – inspected and safe for occupation; yellow – safe for limited entry; red – unsafe, no egress – made selections based on ATC-20 criteria regarding building safety.
Mike Griffin also introduced the electronic version of Rapid Observation of Vulnerability and Estimation of Risk (ROVER), which uses Windows mobile smartphone to gather and transfer data. The open source software remains in development stage but FEMA plans to release it later in 2011.
Mike Conway (11 August 2011)
The southern reach of the San Andreas Fault system, which forms the tectonic boundary between the Pacific and North American tectonic plates, extends south through the Salton Trough to the northern tip of the Sea of Cortez. Each year thousands of earthquakes occur along principal and associated faults, rivaling the most tectonically active areas in the world.
Most events are small (Table 1), with 68% (1181 earthquakes) ranging from 2.5 to 3.5M (NEIC Catalog search does not display events less than 2.5 M). Infrequent large-magnitude events, with a potential to crack irrigation ditches, disrupt roads, and collapse buildings, occur, too. One such event, the El-Mayor-Cucupah M7.2 event, occurred on the Laguna Salada Fault – along the west flank of the Sierra Cucupah in Baja California, Mexico – at 3:40 p.m. (PDT) on 4 April 2010. The nearby communities of Mexicali, Mexico, and Calexico, California, reported damage – some of which was extensive. Fatalities were few and only 100 people were injured.
Following the El Mayor-Cucapah event, aftershocks reportedly occurred at 150 to 200 per day through early May 2010 (Southern California Earthquake Network, http://www.scsn.org/2010sierraelmayor.html).
Table 1. Earthquake events for the southern extent of the San Andreas Fault system cataloged by magnitude.
EQ Magnitude Number of Events
2.5 – 3.5 1181 events
3.5 – 4.5 531 events
4.5 — 5.5 41 events
5.5 – 6.5 1 event
6.5 – 7.5 1 event (El Mayor-Cucupah event)
Total events 1755 events
Data from USGS’s National Earthquake Information Center. Search parameters: Latitude range – 31.5 to 33.5 N; Longitude range – 116.3 to 114.25 W; Date range – 1 April 2010 to 20 May 2011.
The USGS Earthquake Hazards Program hosts individual pages on earthquake information for each of the 50 States. The Arizona page is situated here.
The sorts of things you’ll find there:
- Brief overview of earthquake history of Arizona;
- Quaternary fault information;
- Links to institutions that provide state or regional earthquake information;
- Recent seismicity map;
- Seismic hazard map;
- Latest earthquakes in Arizona.
For a quick overview it is an excellent resource.
Mike Conway (22 May 2011)
Chris Scholtz, seismologist with Lamont-Doherty Earth Observatory, waxes philosophical
about lessons learned from Japan’s 9.0 M earthquake near Sendai. Check out this excellent video from State of the Planet: Lessons from the Japan Earthquake.
It turns out that hazard mapping, which drew on 300 years of historical records, did not serve as well as expected. In A.D. 869, an earthquake sent a tsunami miles inland – a prequel to this year’s major event. And it was not the first time either. But ancient events (ancient for historical purposes), were not included in the hazard analysis, which relied on recent and better documented events.
The moral of the story: don’t eschew tales or legends of catastrophic events simply because they don’t reconcile with recent events.
Video length – 5:52 minutes.
Mike Conway, 18 April 2011
According to the National Academy of Sciences that title characterizes the state of U.S. resilience in the face of a major earthquake. Following on the heels of the recent 9.0 M earthquake in Japan, the news is a little unsettling, if not unexpected.
The 244-page Academy report, National Earthquake Resilience: Research, Implementation, and Outreach, spells out in detail a 20-year plan for strengthening U.S. resilience. The plan includes 18-tasks, reprinted below from their news release. The section titled, “What does an earthquake-resilient community look like? “ (p. 24) seems particularly worthy of review.
Moving forward along the Academy’s 20-year road map requires the collective will to surmount formidable political and budgetary obstacles. But lessons learned from Hurricane Katrina and the Japanese experience should sufficiently motivate the scientific and civic communities to join forces to increase earthquake safety and preparedness in the U.S.
1. Undertake additional research to improve understanding of earthquake phenomena and to increase earthquake-prediction capabilities.
2. Deploy the remaining 75 percent of the Advanced National Seismic System, which provides magnitude and location alerts within a few minutes after an earthquake as well as the basic data for many of the road map tasks.
3. Evaluate, test, and deploy earthquake early-warning systems.
4. Complete coverage of national and urban seismic hazard maps to identify at-risk areas.
5. Develop and implement earthquake forecasting to provide communities with information on how seismic hazards change with time.
6. Develop scenarios that integrate earth science, engineering, and social science information so that communities can visualize earthquake and tsunami impacts and mitigate potential effects.
7. Integrate science, engineering, and social science information in an advanced GIS-based platform to improve earthquake risk assessment and loss estimation.
8. Model expected and improvised emergency response and recovery activities and outcomes to improve pre-disaster mitigation and preparedness.
9. Capture, disseminate, and create a repository of the critical information that describes the geological, structural, institutional, and socio-economic impacts and disaster response after earthquakes occur.
10. Support social sciences research to evaluate mitigation and recovery.
11. Establish an observatory network to measure, monitor, and model the disaster vulnerability and resilience of communities.
12. Integrate the knowledge gained from many of the tasks to enable accurate simulations of fault rupture, seismic wave propagation through bedrock, and soil-structure interaction to understand the response of buildings and other structures to shaking and compute reliable estimates of financial loss, business interruption, and casualties.
13. Develop new techniques for evaluating and retrofitting existing buildings to better withstand earthquakes.
14. Enhance performance-based engineering to achieve better building design and enable improved codes and standards for buildings and other structures.
15. Review and update standards so that critical “lifeline” infrastructure — such as electricity, highways, and water supply — can function following an earthquake.
16. Develop and deploy the next generation of “green” high-performance construction materials and components for use in buildings’ seismic framing systems.
17. Encourage and coordinate technology transfer between the NEHRP and the private sector.
18. Initiate earthquake resiliency pilot projects in local communities to improve awareness, reduce risk, and enhance emergency preparedness and recovery capacity.
Mike Conway, 1 April 2011
Earthquakes are front and center in the global news arena; an M 9.0 event accompanied by tsunami and horrific cascading events will do that. The US Geological Survey has done a marvelous job of showcasing web resources that inform and educate the public to the nature of earthquakes, the Earth’s interior, and the role of plate tectonics. USGS Earthquake Hazards Program
For a crash course in the phenomena of seismicity, there is no better place to start.