1. Geographic Patterns and Profiling of Illegal Land Border Crossings D. Kim Rossmo Quint C. Thurman

2. Border Control  Geographic range  Porous nature  US national security  Significant challenge Rugged terrain of El Paso border

3. The Illegal Border Crossing “Arms Race” Ground sensor and UAV Fencing and electronic gate Trucks in Rio Grande canyon Inner tubes along the Rio Grande

5. Berlin Wall  10,315 days  August 1961 to November 1989  East / West Berlin border 27 miles  West Berlin border 96 miles  12-foot wall, 302 watch towers, 20 bunkers  192 deaths, 200 shooting injuries  5,000 escapes (3.4 per week)

6. US Border Patrol Sectors

7. Texas- Mexico Border  1,000 miles  52% of southern border  1,933 miles  50% federal land

8. Theoretical Perspective  Criminal behavior  Bounded rationality  Shaped by personal and environmental factors  Migration theory  Origin (push) factors  Destination (pull) factors)  Distance (effort, time, money)  Cost/benefit (risk/reward) analysis framework

9. Illegal Border Crossing Requirements  Trip origin  Border  Staging area  Crossing  Landing  Trip destination

10. Premise  Identify border crossing factors  Facilitating  Inhibiting  Determine features related to probability of illegal border movement  Environmental  Physical

11. US Border Patrol Data  2001 to 2004 (4 years)  1 to 1.6 million cases annually in the US  20 to 25% of these cases are in Texas  Laredo, McAllen, Del Rio, Marfa, and El Paso Sectors

12.  Dependent  Illegal Texas-Mexico land border crossings  Independent  Physical geography  Human geography Research Variables

13. Preliminary Focus Area  Del Rio Border Patrol Sector  Val Verde, Kinney, & Maverick Counties  111 Landmark Mile Markers (170 miles)

15. Physical Geography  Hydrography  Terrain  Vegetation  Temperature (day and night)

16. Hydrography  Types of features  Streams  Rivers  Lakes  Reservoirs  Data sources  US Census (USA)  INEGI (Mexico)

17. Terrain (USGS DEM)  Extent  All counties  Mexico overlap  Primary Output  Elevation  Slope  Aspect  Hillshade  Identification  Ravines  Gullies

19. Vegetation  Types of features  Brush  Crops  Parks  Woods  Data sources  TPWD (US)  INEGI (Mexico)

20. Temperature  Monthly normals  Minimum  Maximum  Annual normals  Mean

21. Human Geography Variables  Major transportation  Population density  Urban developments  Political region  Additional features

22. Major Transportation  Types  Airports  Railroads  Roads  Bridges  US data sources  US Census  TCEQ  Mexico data sources  GeoCommunity

23. Population Density & Urban Development  US data  2000 US Census  All counties  Mexico Data  1990 Census  Mexico

28. Del Rio Illegal Border Crossings

29. Del Rio Illegal Border Crossings (Cumulative %) G = 0.64 ID = 0.49

30. Del Rio Sector – All Illegal Entries 2000 14,520 2001 86,974 2002 61,974 2003 53,744 2004 37,534 2000-04254,717

31. All Entries

32. Del Rio Sector – Criminal Entries 2000 - 2001 5 2002 129 2003 289 2004 162 2000-04 585

33. Criminal Entries

34. Density of Del Rio Sector Illegal Entries

43. Residence Country (Excluding Mexico)

44. US or Mexico State of Birth

45. Gender

46. Apprehension Age

47. Distance to United States Urban Areas

48. Distance to Mexico Urban Areas

49. Slope Least Cost Path  Cost-weighted distance (higher slope = greater cost)  Cost-weighted direction (least cost direction to source)  Least cost path (to rural highway segments)

50. Combined Slope Cost-Weighted Distance  Top 10 criminal disposition entry Landmark Mile Markers  Weighted by number of criminal disposition entries  323 total entries

51. Slope Cost Distance Analysis  Travel across terrain values is more difficult (higher “cost”)  Border areas with low slope cost values are attractive to illegal border crossers

52. Elevation Change Analysis  Border areas with higher elevation on the Mexico side are attractive to illegal border crossers  Elevation differentials allows for surveillance of US Border Patrol vehicles

53. Viewshed Analysis  The viewshed (line of sight) identifies all locations visible from a given point  Areas with low viewshed values are attractive to illegal border crossers due to low detection risk

54. Illegal Border Crosser Population Estimates  Official estimates: +10 to 50%  Line officer estimates: +100%

55. Capture-Recapture Analysis P S1S1 S2S2 O P = S 1 S 2 O ?

56. Scholarly Outcomes  Illegal movements  International migration  Spatial displacement  Natural and built factors  Microlevel environmental influences

57. Practical Products  US Border Patrol operations  Unidentified crossing points  Displacement anticipation  Criminal and drug interdiction  Counter-terrorism applications  Training