Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Understanding risk to Seattle's high-rise buildings from a giant Cascadian earthquake

14.04.2009
The Cascadia subduction zone is likely to produce the strongest shaking experienced in the lower 48 states. Although seismic activity in the Pacific Northwest has been relatively low in the past two centuries, there is a growing consensus that this fault zone ruptures in giant earthquakes (magnitude exceeding 9); the last rupture is inferred to have occurred in 1700.

What is the risk to high-rise buildings from such a giant earthquake? Although four giant subduction earthquakes occurred elsewhere in the past century, there were no cities with high-rise buildings in the heavily shaken areas for any of these events. Furthermore, ground motions have never been recorded in areas strongly shaken by a giant earthquake.

T. Heaton and J. Yang of Caltech simulated ground shaking from an earthquake similar to the giant Sumatran earthquake (M 9.2) that occurred in 2004, and which is hypothesized to be similar to the giant earthquakes in the Pacific Northwest. The simulated shaking lasts for more than four minutes and it is dominated by low frequency motions. While smaller buildings (e.g., wooden houses) are not particularly susceptible to these low frequency motions, tall buildings resonate at the low frequencies contained in these simulations. The Seattle basin exacerbates the situation by significantly amplifying these long-period motions in the Seattle metropolitan area. Heaton and Yang simulated the response of modern steel 6- and 20-story buildings to the hypothetical ground motions. Although there are many unanswered questions about such a future earthquake, they report that severe damage and possible collapse is indicated in many of their simulations.

Buildings that were constructed prior to important building code changes that were made as a result of the 1994 Northridge earthquake are especially vulnerable to this long period shaking. Heaton and Yang report that, given the current state of understanding, there is insufficient knowledge of ground shaking and of building response to ensure the integrity of tall buildings in such an earthquake.

SSA is a scientific society devoted to the advancement of earthquake science. Founded in 1906 in San Francisco, the Society now has members throughout the world representing a variety of technical interests: seismologists and other geophysicists, geologists, engineers, insurers, and policy-makers in preparedness and safety.

Nan Broadbent | EurekAlert!
Further information:
http://www.msn.com

More articles from Earth Sciences:

nachricht Sediment from Himalayas may have made 2004 Indian Ocean earthquake more severe
26.05.2017 | Oregon State University

nachricht Devils Hole: Ancient Traces of Climate History
24.05.2017 | Universität Innsbruck

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>