Hazards- Case Studies Flashcards
Where is Kobe located and on which fault did the 1995 earthquake occur?
Kobe is in the Kansai region of Japan; the quake struck along the Nojima Fault, part of the southern extension of the Japan Median Tectonic Line.
When did the 1995 Kobe earthquake occur, and what were its magnitude and epicentral depth?
It occurred on 17 January 1995 at 05:46 JST; magnitude Mw 6.9 at a depth of 16 km.
What was the plate boundary setting of the Kobe earthquake?
A convergent boundary between the Philippine Sea Plate (Nojima Fault) and the Eurasian Plate.
Describe the primary impacts of the 1995 Kobe earthquake.
Over 6,400 deaths, ~300,000 buildings damaged or destroyed, widespread homelessness and major ground fissures.
Explain how liquefaction contributed to the damage in Kobe.
Saturated, reclaimed land lost strength under shaking, causing buildings, roads and railways to collapse or tilt.
Assess one secondary hazard that worsened the Kobe event’s destruction.
Urban fires broke out due to ruptured gas mains and toppled electrical infrastructure, compounding structural losses.
Evaluate the immediate emergency response and utility restoration after the Kobe quake.
Rapid deployment of JSDF and firefighting units, but many areas lacked water pressure; power and water were fully restored only weeks later.
Discuss one long-term reconstruction effort and regulatory change post-1995 Kobe earthquake.
Implementation of stricter seismic building codes, mandatory retrofitting of vulnerable structures and community earthquake drills.
What was the date, path and strength category of Hurricane Katrina at U.S. landfall?
Landfall on 29August2005 near Buras-Triumph, Louisiana, as a Category3 storm (sustained winds ~185 km/h).
Which regions suffered the worst storm surge and why was New Orleans particularly vulnerable?
Gulf Coast areas (Mississippi coast, Lake Pontchartrain); New Orleans was below sea level and reliant on levees that failed.
Describe the primary physical impacts of Hurricane Katrina.
Widespread flooding inundating 80% of New Orleans, ~1,800 fatalities, displacement of over 1 million people.
Analyze two environmental consequences of Hurricane Katrina.
Coastal marsh erosion and destruction, large-scale oil spills and contamination from ruptured storage facilities.
Evaluate the effectiveness of evacuation orders and shelter provisions during Katrina.
Mandatory evacuations issued but many lacked transport; Superdome overcrowded and understaffed; slower-than-needed federal response.
Discuss one policy reform enacted after criticisms of FEMA’s Katrina response.
Reform of the Robert T. Stafford Act, enhanced FEMA authority, and restructuring of the National Response Framework.
Talk about the tectonic setting of the Eyjafjallajökull eruption.
Constructive margin on the Mid-Atlantic Ridge where North American and Eurasian plates diverge beneath southern Iceland.
Eyjafjallajökull eruption—build-up to the event?
Small seismic swarms began in December2009, followed by dike intrusion and ground deformation under the glacier in early 2010.
Eruptive history of Eyjafjallajökull prior to 2010?
Multiple eruptions recorded since the 10thcentury, including in 1612, 1821–23, typically small basaltic fissure events.
Eyjafjallajökull eruption magma types?
Predominantly andesitic to basaltic-andesitic; moderate silica yields both effusive lava and explosive ash phases.
What are the main primary effects of the Eyjafjallajökull ash cloud?
Ash plume reached ~9 km, closing European airspace for five days, ash deposition damaging machinery and crops.
What were the main secondary effects of the 2010 eruption?
Economic losses estimated at €2billion to €5billion, disruptions in supply chains, and increased respiratory issues.
How is Eyjafjallajökull monitored to mitigate future eruptions?
IMO network tracks seismicity, GPS ground deformation, IR imagery, gas emissions, and meltwater outflow rates.
Why is Katla considered a future hazard after the 2010 eruption?
Katla lies beneath the Mýrdalsjökull ice cap, historically erupts shortly after Eyjafjallajökull, with larger VEI and jökulhlaups.
Specify the date, magnitude, depth and plate boundary for the 2011 Tōhoku earthquake.
11March2011; Mw9.0; ~30 km depth; Pacific Plate subducting beneath Okhotsk Plate off Japan’s east coast.
Compare the seismic energy of the Tōhoku quake with the 2004 Indian Ocean event.
Released ~500megaton TNT equivalent vs ~220megaton for 2004; roughly twice the energy.
