More about New Madrid Fault Zone for Operation Shaky Endeavor 2014

THE NEW MADRID FAULT SYSTEM EXTENDS 120 MILES SOUTHWARD from the area of Charleston, Missouri, and Cairo, Illinois, through New Madrid and Caruthersville, following Interstate 55 to Blytheville and on down to Marked Tree, Arkansas. It crosses five state lines and cuts across the Mississippi River in three places and the Ohio River in two places.

THE FAULT IS ACTIVE, AVERAGING MORE THAN 200 MEASURED EVENTS per YEAR (1.0 or more on the Richter scale), about 20 per month. Tremors large enough to be felt (2.5 - 3.0 on the Richter scale) are noted annually. Every 18 months the fault releases a shock of 4.0 or more, capable of local minor damage. Magnitudes of 5.0 or greater occurring about once per decade, can do significant damage, and be felt in several states.

The Wabash Valley Seismic Zone consists largely of vertically-oriented ("normal") faults deeply buried under layers of sediment. Although the tectonics of the region are still not fully understood and are the subject of ongoing research, these faults are thought by some to be associated with a branch of the New Madrid aulacogen, an old rift zone where the lithosphere actively began to pull apart at perhaps two separate times in the distant past. The crust in the area has been weakened by the numerous faults, which remain active sites for continuing seismic activity as the motion of the North American Plate exerts both compressional and tensional forces.

The fault system actually contains two types of faults, a strike slip segment oriented to the northeast, running from Marked Tree, AR to Caruthersville, MO, and a northwest trending reverse fault that rests below the New Madrid region. Material on the northwest side of the strike-slip fault moves northeast, and up the ramp.

Significant ground motion at greater distance in the Central US than in the Western US.

Due to dispersion of the waves, distant structures may be placed into resonance. Long or tall structures are particularly susceptible to

resonance effects. More distant towns: tall buildings in Chicago; bridges

across major rivers; dams; pipelines. Evaluation of geotechnical issues: activation of

slides, liquefaction/lateral spreading, bearing capacity, differential settlement.

Surface fault rupture (Not often seen in NMSZ)

Ground waves and fling effects Topographic enhancement of seismic energy Dynamic consolidation of soils (Settling –

likely) Liquefaction and lateral spreading (Likely) Site amplification effects (Likely) Long period motion and resonant frequency

effects Out-of of-phase structural response

Fill embankments tend to consolidate and settle under dynamic loading in the near-field zone

Approach fills for pile supported bridges commonly exhibit grievous differential settlement

Lateral spreads can exhibit different Lateral length-to-depth ratios, depending on soil sensitivity. Liquefaction occurs along discrete horizons which are confined, allowing lateral translation of rafted material, usually towards open channels or depressions.

Block diagram of a lateral spread which evolved from post -1964 earthquake evaluations in Alaska by Walt Hansen inUSGS Professional Paper 542 542-A (1966)

Pipeline ruptures/interruptions Main power system disruptions Communications interruptions/overloads

Microwave link disruptions – misalignment Systems down due to power interruptions

Transportation interruptions Bridges/highways Public transport

Injects 8 to 10 per hour for local jurisdictions Similar number at regional level Addressing infrastructure issues, fires, structure damage

Exact nature of injects is TBD at this point Likely to be assessment of infrastructure damage▪ Pipelines – out of the picture▪ Bridges – out of the picture▪ Transportation▪ Communications▪ Electrical, etc.

Exercise Limitations

Date/Time TBD Purpose/Objectives

Provide Emergency Communications Off the main power systems Operation in accordance with EOP Orderly nets with properly handled traffic

Injects will be provided with specific timelines.

Regional communications linked by microwave may not function EOCs may be out of contact with county and regional centers Unable to contact Fire, EMS and Law Enforcement

Alternate systems may be required No-one does alternate like Amateur Radio does alternate AR may be called upon to provide communications between

EOCs Amateurs bring their own systems

Portable power and communications systems Self-imposed conservation of resources Local and regional communications Critical contact with SEMA