Alternatively, the New Madrid seismic zone is geologically young feature that has been active for only the last few tens of thousands of years. Zoback and Zoback have suggested such a model for intraplate seismicity in general. That is, the geological and geodetic observations that suggest relatively short recurrence intervals reflect a time of high, but geologically temporary, pore-fluid pressure.
![new madrid seismac zone length new madrid seismac zone length](https://3.bp.blogspot.com/-k5_h1g5zuT8/TlVJE-loEjI/AAAAAAAAMe0/Huf37aEj19o/s1600/nuke1map.gif)
A second possibility is that activity in the region is cyclic. One is that the seismological and geodetic evidence are misleading. There are at least three possible interpretations of the observations of short recurrence intervals and high strain rates, but apparently youthful fault geometry and lack of major post-Miocene deformation. Moreover, the irregular fault pattern forming a compressive step that one sees today is not compatible with large displacements. No subsurface evidence for such large displacements is known within the seismic zone. Recurrence intervals of this order should have produced about 50 km of strike-slip offset since Miocene time. These estimates are supported by some geological and GPS results. The study makes recommendations for further research and implementation, including methods to perform future post-earthquake damage assessments and building evaluations.Frequency-magnitude relations in the New Madrid seismic zone suggest that great earthquakes should occur every 700-1,200 yrs, implying relatively high strain rates. Additionally, recent studies of paleoseismology and magnitude estimation have improved the understanding of the past behavior of the NMSZ, whereas questions remain open as to the future behavior of the NMSZ.
![new madrid seismac zone length new madrid seismac zone length](https://i0.wp.com/thegreatrecession.info/blog/wp-content/uploads/madridzone.jpg)
The study makes several concludes that deterministic capping of ground motions in the immediate vicinity of the modeled faults in the NMSZ should be considered for establishing design level ground motions, and hazard de-aggregation represents a useful and practical tool for communicating concepts and sources of seismic hazard to the stakeholders in a more transparent manner. This high level of seismic hazard is evidenced by large earthquakes that have repeatedly occurred in the past reaching destructive magnitudes. Results of this study further confirm the high level of seismic hazard in the NMSZ and the need for continued attention to and consideration of adequate mitigation measures. The study aims to communicate the level of uncertainties involved in the seismic hazard assessment procedures and their impact on the assignment of seismic design ground motions and categories and to provide recommendations regarding implications associated with adoption or modification of newer seismic hazard provisions found in the IBC-2000 and IRC-2000. This approach to magnitude assessment is particularly appealing given that the magnitude estimate is ultimately used for regulation of building construction through the use of seismic hazard maps that are integral with seismic design provisions in modern building codes.
New madrid seismac zone length series#
Furthermore, a series of structural fragility evaluations of historic accounts of building damage are conducted to provide additional and independent constraints on the magnitude estimates of the 1811-1812 earthquakes. This study provides an overview of the seismic hazard characterization procedures used in the NMSZ and implemented in the IBC-2000 and IRC-2000.
New madrid seismac zone length code#
The seismic design provisions of the International Building Code (IBC-2000) and the International Residential Code (IRC-2000) are both currently being considered for adoption by local political jurisdictions across the U.S., and have generated much concern and controversy as to the accuracy and validity of the new seismic provisions in the Central and Eastern United States, and particularly in the New Madrid Seismic Zone (NMSZ).
![new madrid seismac zone length new madrid seismac zone length](http://endoftheamericandream.com/wp-content/uploads/2014/08/Earthquake-Map.jpg)
![new madrid seismac zone length new madrid seismac zone length](https://i.pinimg.com/originals/86/0c/fd/860cfdb622ee9d1b2a1ff5683d2e1e0a.jpg)
Seismic hazard assessments affect building code design requirements (i.e., mapped design ground motions), construction guidelines, building costs, insurance rates, expected consequences of future earthquake activity, and regional economies as a whole. While housing construction in the United States is generally considered to be earthquake-resistant in comparison to many forms of construction found worldwide, the assessment of seismic hazard has significant implications with regard to the balance of housing affordability and safety. The assessment of earthquake hazard has been a long-standing concern in areas known to be prone to earthquakes.