hf radar detection of tsunamis
play

HF Radar detection of tsunamis Belinda Lipa, James Isaacson, Bruce - PowerPoint PPT Presentation

HF Radar detection of tsunamis Belinda Lipa, James Isaacson, Bruce Nyden, Donald Barrick Codar Ocean Sensors Analysis for tsunami current velocities, water levels Two radars measure radial current velocity maps Radial velocities are


  1. HF Radar detection of tsunamis Belinda Lipa, James Isaacson, Bruce Nyden, Donald Barrick Codar Ocean Sensors

  2. Analysis for tsunami current velocities, water levels • Two radars measure radial current velocity maps • Radial velocities are combined to give total velocity • Velocities are detrended to estimate the tsunami component • Water level is calculated from detrended velocity & water depth

  3. Hokkaido tsunami Current velocities and water levels

  4. Tsunami detection summary .

  5. Velocity oscillations during the 2011 Japan tsunami

  6. From 2 hrs before the quake until 5 hrs after Around the tsunami arrival

  7. Typical velocity patterns signaling tsunami arrival Hokkaido, Japan Oregon, USA Bodega Bay Pt. Reyes California California

  8. PATTERN RECOGNITION: FOUR STEPS Step 1: Define the “Velocity deviation function” V D (t)

  9. Step 2: Define the “Velocity correlation function” V C (t) 14 12 Velocity (cm/s) 10 8 6 4 2 0.8 0.9 1 1.1 1.2 Time from earthquake (hours)

  10. Example 1: Japan earthquake, March 2011 Kinaoshi, Hokkaido Velocity q-factor (a) (b) 15 12000 10000 10 Bands 1-3 8000 Velocity (cm/s) q factor) 6000 5 4000 2000 0 0 -5 -2000 -2 -1 0 1 2 -2 -1 0 1 2 Time from earthquake (hours) Time from earthquake (hours) (c) (d) 15 12000 Bands 4-6 10000 10 8000 Velocity (cm/s) q factor) 6000 5 4000 2000 0 0 -5 -2000 -2 -1 0 1 2 -2 -1 0 1 2 Time from earthquake (hours) Time from earthquake (hours)

  11. Example 2 Japan earthquake, March 2011 Yaquina Head, Oregon Velocity q-factor (a) 4 (b) x 10 20 5 15 0 Veocity (cm/s) 10 q factor) -5 Bands 2-4 5 -10 0 -15 -5 -10 -20 0 1 2 3 4 0 1 2 3 4 Hours from March 11, 12:00 UTC Hours from March 11, 12:00 UTC (c) 5 (d) x 10 20 0.5 15 0 -0.5 Veocity (cm/s) 10 q factor) -1 5 Bands 4-6 -1.5 0 -2 -5 -2.5 -10 -3 0 1 2 3 4 0 1 2 3 4 Hours from March 11, 12:00 UTC Hours from March 11, 12:00 UTC

  12. Example 3: Indonesia earthquake April 2012 Velocity q-factor Padang, Sumatra Hut Bay, India

Recommend


More recommend